<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/BasisOfPresentation" xlink:href="moh-20170630.xsd#BasisOfPresentation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/BasisOfPresentationDetails" xlink:href="moh-20170630.xsd#BasisOfPresentationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/CommitmentsAndContingencies" xlink:href="moh-20170630.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/CommitmentsAndContingenciesDetails" xlink:href="moh-20170630.xsd#CommitmentsAndContingenciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ConsolidatedBalanceSheets" xlink:href="moh-20170630.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="moh-20170630.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="moh-20170630.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ConsolidatedStatementsOfCashFlowsParenthetical" xlink:href="moh-20170630.xsd#ConsolidatedStatementsOfCashFlowsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ConsolidatedStatementsOfComprehensiveLossIncome" xlink:href="moh-20170630.xsd#ConsolidatedStatementsOfComprehensiveLossIncome" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ConsolidatedStatementsOfOperations" xlink:href="moh-20170630.xsd#ConsolidatedStatementsOfOperations" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/Debt" xlink:href="moh-20170630.xsd#Debt" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/DebtAdditionalInformationDetails" xlink:href="moh-20170630.xsd#DebtAdditionalInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/DebtScheduleOfLongTermDebtDetails" xlink:href="moh-20170630.xsd#DebtScheduleOfLongTermDebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/DebtTables" xlink:href="moh-20170630.xsd#DebtTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/Derivatives" xlink:href="moh-20170630.xsd#Derivatives" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/DerivativesDetails" xlink:href="moh-20170630.xsd#DerivativesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/DerivativesTables" xlink:href="moh-20170630.xsd#DerivativesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/DocumentAndEntityInformation" xlink:href="moh-20170630.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/FairValueMeasurements" xlink:href="moh-20170630.xsd#FairValueMeasurements" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/FairValueMeasurementsDetailsOfLongTermDebtDetails" xlink:href="moh-20170630.xsd#FairValueMeasurementsDetailsOfLongTermDebtDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/FairValueMeasurementsFairValueOfFinancialInstrumentsOnRecurringBasisDetails" xlink:href="moh-20170630.xsd#FairValueMeasurementsFairValueOfFinancialInstrumentsOnRecurringBasisDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/FairValueMeasurementsTables" xlink:href="moh-20170630.xsd#FairValueMeasurementsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ImpairmentLosses" xlink:href="moh-20170630.xsd#ImpairmentLosses" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ImpairmentLossesAdditionalInformationDetails" xlink:href="moh-20170630.xsd#ImpairmentLossesAdditionalInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ImpairmentLossesGoodwillBalancesDetails" xlink:href="moh-20170630.xsd#ImpairmentLossesGoodwillBalancesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/ImpairmentLossesTables" xlink:href="moh-20170630.xsd#ImpairmentLossesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/Investments" xlink:href="moh-20170630.xsd#Investments" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/InvestmentsAvailableForSaleInvestmentsDetails" xlink:href="moh-20170630.xsd#InvestmentsAvailableForSaleInvestmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/InvestmentsContractualMaturitiesOfInvestmentsDetails" xlink:href="moh-20170630.xsd#InvestmentsContractualMaturitiesOfInvestmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/InvestmentsHeldToMaturityInvestmentsDetails" xlink:href="moh-20170630.xsd#InvestmentsHeldToMaturityInvestmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/InvestmentsSummaryOfInvestmentsDetails" xlink:href="moh-20170630.xsd#InvestmentsSummaryOfInvestmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/InvestmentsTables" xlink:href="moh-20170630.xsd#InvestmentsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayable" xlink:href="moh-20170630.xsd#MedicalClaimsAndBenefitsPayable" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayableAdditionalInformationDetails" xlink:href="moh-20170630.xsd#MedicalClaimsAndBenefitsPayableAdditionalInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayableComponentsOfChangeInMedicalClaimsAndBenefitsPayableDetails" xlink:href="moh-20170630.xsd#MedicalClaimsAndBenefitsPayableComponentsOfChangeInMedicalClaimsAndBenefitsPayableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayableMedicalClaimsAndFutureBenefitsDetails" xlink:href="moh-20170630.xsd#MedicalClaimsAndBenefitsPayableMedicalClaimsAndFutureBenefitsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayableTables" xlink:href="moh-20170630.xsd#MedicalClaimsAndBenefitsPayableTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/NetLossIncomePerShare" xlink:href="moh-20170630.xsd#NetLossIncomePerShare" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/NetLossIncomePerShareDetail" xlink:href="moh-20170630.xsd#NetLossIncomePerShareDetail" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/NetLossIncomePerShareTables" xlink:href="moh-20170630.xsd#NetLossIncomePerShareTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/RelatedPartyTransactions" xlink:href="moh-20170630.xsd#RelatedPartyTransactions" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/RelatedPartyTransactionsDetails" xlink:href="moh-20170630.xsd#RelatedPartyTransactionsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/RestructuringAndSeparationCosts" xlink:href="moh-20170630.xsd#RestructuringAndSeparationCosts" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/RestructuringAndSeparationCostsExpectedCostsDetails" xlink:href="moh-20170630.xsd#RestructuringAndSeparationCostsExpectedCostsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/RestructuringAndSeparationCostsOtherRestructuringCostsDetails" xlink:href="moh-20170630.xsd#RestructuringAndSeparationCostsOtherRestructuringCostsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/RestructuringAndSeparationCostsSeparationCostsDetails" xlink:href="moh-20170630.xsd#RestructuringAndSeparationCostsSeparationCostsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/RestructuringAndSeparationCostsTables" xlink:href="moh-20170630.xsd#RestructuringAndSeparationCostsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SegmentInformation" xlink:href="moh-20170630.xsd#SegmentInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SegmentInformationAdditionalInformationDetails" xlink:href="moh-20170630.xsd#SegmentInformationAdditionalInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SegmentInformationReconciliationOfGrossMarginToConsolidatedIncomeDetails" xlink:href="moh-20170630.xsd#SegmentInformationReconciliationOfGrossMarginToConsolidatedIncomeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SegmentInformationScheduleOfOperatingSegmentInformationDetails" xlink:href="moh-20170630.xsd#SegmentInformationScheduleOfOperatingSegmentInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SegmentInformationTables" xlink:href="moh-20170630.xsd#SegmentInformationTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SignificantAccountingPolicies" xlink:href="moh-20170630.xsd#SignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SignificantAccountingPolicies3RProgramReceivablesPayablesDetails" xlink:href="moh-20170630.xsd#SignificantAccountingPolicies3RProgramReceivablesPayablesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SignificantAccountingPoliciesAdditionalInformationDetails" xlink:href="moh-20170630.xsd#SignificantAccountingPoliciesAdditionalInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SignificantAccountingPoliciesPolicies" xlink:href="moh-20170630.xsd#SignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SignificantAccountingPoliciesQualityIncentivePremiumRevenueRecognizedDetails" xlink:href="moh-20170630.xsd#SignificantAccountingPoliciesQualityIncentivePremiumRevenueRecognizedDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SignificantAccountingPoliciesTables" xlink:href="moh-20170630.xsd#SignificantAccountingPoliciesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/StockholdersEquity" xlink:href="moh-20170630.xsd#StockholdersEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/StockholdersEquityAdditionalInformationDetails" xlink:href="moh-20170630.xsd#StockholdersEquityAdditionalInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/StockholdersEquityShareActivityDetails" xlink:href="moh-20170630.xsd#StockholdersEquityShareActivityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/StockholdersEquityTables" xlink:href="moh-20170630.xsd#StockholdersEquityTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformation" xlink:href="moh-20170630.xsd#SupplementalCondensedConsolidatingFinancialInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationAdditionalInformationDetails" xlink:href="moh-20170630.xsd#SupplementalCondensedConsolidatingFinancialInformationAdditionalInformationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationBalanceSheetDetails" xlink:href="moh-20170630.xsd#SupplementalCondensedConsolidatingFinancialInformationBalanceSheetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationCashFlowsDetails" xlink:href="moh-20170630.xsd#SupplementalCondensedConsolidatingFinancialInformationCashFlowsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationComprehensiveIncomeLossDetails" xlink:href="moh-20170630.xsd#SupplementalCondensedConsolidatingFinancialInformationComprehensiveIncomeLossDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationStatementsOfOperationsDetails" xlink:href="moh-20170630.xsd#SupplementalCondensedConsolidatingFinancialInformationStatementsOfOperationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationTables" xlink:href="moh-20170630.xsd#SupplementalCondensedConsolidatingFinancialInformationTables" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/VariableInterestEntitiesVies" xlink:href="moh-20170630.xsd#VariableInterestEntitiesVies" xlink:type="simple" />
  <link:roleRef roleURI="http://www.molinahealthcare.com/role/VariableInterestEntitiesViesDetails" xlink:href="moh-20170630.xsd#VariableInterestEntitiesViesDetails" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/BasisOfPresentation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/BasisOfPresentationDetails" xlink:type="extended">
    <link:loc xlink:href="moh-20170630.xsd#moh_BasisOfPresentationLineItems" xlink:label="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:type="locator" />
    <link:loc xlink:href="moh-20170630.xsd#moh_BasisOfPresentationTable" xlink:label="loc_moh_BasisOfPresentationTable_940AEBC09D60E5DD39A39FB483CA3514" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_moh_BasisOfPresentationTable_940AEBC09D60E5DD39A39FB483CA3514" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="loc_us-gaap_MajorCustomersAxis_69978CF6F7372D42F4A19FB483CAB9E8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_BasisOfPresentationTable_940AEBC09D60E5DD39A39FB483CA3514" xlink:to="loc_us-gaap_MajorCustomersAxis_69978CF6F7372D42F4A19FB483CAB9E8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_4AA4F5D37F8258C410629FB483CA934D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorCustomersAxis_69978CF6F7372D42F4A19FB483CAB9E8" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_4AA4F5D37F8258C410629FB483CA934D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_4AA4F5D37F8258C410629FB483CA934D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorCustomersAxis_69978CF6F7372D42F4A19FB483CAB9E8" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_4AA4F5D37F8258C410629FB483CA934D" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MississippiCoordinatedAccessNetworkMember" xlink:label="loc_moh_MississippiCoordinatedAccessNetworkMember_F71E61C8F41B7147EDE59FB483CAC8F9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_4AA4F5D37F8258C410629FB483CA934D" xlink:to="loc_moh_MississippiCoordinatedAccessNetworkMember_F71E61C8F41B7147EDE59FB483CAC8F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainContingenciesByNatureAxis" xlink:label="loc_us-gaap_GainContingenciesByNatureAxis_625EA64F1B6DC13A0BA29FB483CA1FAB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_BasisOfPresentationTable_940AEBC09D60E5DD39A39FB483CA3514" xlink:to="loc_us-gaap_GainContingenciesByNatureAxis_625EA64F1B6DC13A0BA29FB483CA1FAB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainContingencyNatureDomain" xlink:label="loc_us-gaap_GainContingencyNatureDomain_8D7C34DAF6D25622C1429FB483CBED51_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GainContingenciesByNatureAxis_625EA64F1B6DC13A0BA29FB483CA1FAB" xlink:to="loc_us-gaap_GainContingencyNatureDomain_8D7C34DAF6D25622C1429FB483CBED51_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GainContingencyNatureDomain" xlink:label="loc_us-gaap_GainContingencyNatureDomain_8D7C34DAF6D25622C1429FB483CBED51" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GainContingenciesByNatureAxis_625EA64F1B6DC13A0BA29FB483CA1FAB" xlink:to="loc_us-gaap_GainContingencyNatureDomain_8D7C34DAF6D25622C1429FB483CBED51" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_AcquisitionContractTerminationMember" xlink:label="loc_moh_AcquisitionContractTerminationMember_E06208058B49EE56DEE49FB483CB7146" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GainContingencyNatureDomain_8D7C34DAF6D25622C1429FB483CBED51" xlink:to="loc_moh_AcquisitionContractTerminationMember_E06208058B49EE56DEE49FB483CB7146" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_51B13523EF9EC5179E3F9FB483CB7442" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_BasisOfPresentationTable_940AEBC09D60E5DD39A39FB483CA3514" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_51B13523EF9EC5179E3F9FB483CB7442" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_53D233DB12B59FF91F649FB483CBE34B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_51B13523EF9EC5179E3F9FB483CB7442" xlink:to="loc_us-gaap_SegmentDomain_53D233DB12B59FF91F649FB483CBE34B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_53D233DB12B59FF91F649FB483CBE34B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_51B13523EF9EC5179E3F9FB483CB7442" xlink:to="loc_us-gaap_SegmentDomain_53D233DB12B59FF91F649FB483CBE34B" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_HealthPlansMember" xlink:label="loc_moh_HealthPlansMember_A9835CA8CE27A6C701319FB483CB7DF0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_53D233DB12B59FF91F649FB483CBE34B" xlink:to="loc_moh_HealthPlansMember_A9835CA8CE27A6C701319FB483CB7DF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_15EB369DE0B70FF910F29FB483CB6409" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_BasisOfPresentationTable_940AEBC09D60E5DD39A39FB483CA3514" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_15EB369DE0B70FF910F29FB483CB6409" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_96B756C6F977FB553A9E9FB483CBF2CF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_15EB369DE0B70FF910F29FB483CB6409" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_96B756C6F977FB553A9E9FB483CBF2CF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_96B756C6F977FB553A9E9FB483CBF2CF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_15EB369DE0B70FF910F29FB483CB6409" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_96B756C6F977FB553A9E9FB483CBF2CF" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_TodaysOptionsOfNewYorkInc.Member" xlink:label="loc_moh_TodaysOptionsOfNewYorkInc.Member_ACB6DDB26A09E0CFF43B9FB483CB9663" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_96B756C6F977FB553A9E9FB483CBF2CF" xlink:to="loc_moh_TodaysOptionsOfNewYorkInc.Member_ACB6DDB26A09E0CFF43B9FB483CB9663" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_78D65AE9384B51DCE7D79FB483CB8CAE" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_BasisOfPresentationTable_940AEBC09D60E5DD39A39FB483CA3514" xlink:to="loc_us-gaap_StatementGeographicalAxis_78D65AE9384B51DCE7D79FB483CB8CAE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_5E112002D4F55C6539209FB483CB41AC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_78D65AE9384B51DCE7D79FB483CB8CAE" xlink:to="loc_us-gaap_SegmentGeographicalDomain_5E112002D4F55C6539209FB483CB41AC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_5E112002D4F55C6539209FB483CB41AC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementGeographicalAxis_78D65AE9384B51DCE7D79FB483CB8CAE" xlink:to="loc_us-gaap_SegmentGeographicalDomain_5E112002D4F55C6539209FB483CB41AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/stpr/2011/stpr-2011-01-31.xsd#stpr_NY" xlink:label="loc_stpr_NY_80E54756594DED5BA5639FB483CB644D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_5E112002D4F55C6539209FB483CB41AC" xlink:to="loc_stpr_NY_80E54756594DED5BA5639FB483CB644D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:label="loc_us-gaap_NumberOfReportableSegments_398505872A6FFD1E25829FB483CB0D9C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_us-gaap_NumberOfReportableSegments_398505872A6FFD1E25829FB483CB0D9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NumberOfStatesInWhichEntityOperates" xlink:label="loc_us-gaap_NumberOfStatesInWhichEntityOperates_FE347F1D0C172817C4CB9FB483CBD967" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_us-gaap_NumberOfStatesInWhichEntityOperates_FE347F1D0C172817C4CB9FB483CBD967" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_NumberOfMembersEligibleForTheHealthCarePrograms" xlink:label="loc_moh_NumberOfMembersEligibleForTheHealthCarePrograms_89D7F859A9977AB4DD929FB483CC6BA0" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_moh_NumberOfMembersEligibleForTheHealthCarePrograms_89D7F859A9977AB4DD929FB483CC6BA0" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MinimumContractTerm" xlink:label="loc_moh_MinimumContractTerm_93D4E46B427855053CE89FB483CC8AFB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_moh_MinimumContractTerm_93D4E46B427855053CE89FB483CC8AFB" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MaximumContractTerm" xlink:label="loc_moh_MaximumContractTerm_9656A751C664FF3CCD359FB483CCB969" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_moh_MaximumContractTerm_9656A751C664FF3CCD359FB483CCB969" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_C74F5A111835C30639489FB483CC342B" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_us-gaap_RestructuringCharges_C74F5A111835C30639489FB483CC342B" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ServicesContractTerm" xlink:label="loc_moh_ServicesContractTerm_734EB40A98F7BFE84C869FB483CC9475" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_moh_ServicesContractTerm_734EB40A98F7BFE84C869FB483CC9475" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ServicesContractRenewalTerm" xlink:label="loc_moh_ServicesContractRenewalTerm_D55E85BB3102928A62D49FB483CC7BAB" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_moh_ServicesContractRenewalTerm_D55E85BB3102928A62D49FB483CC7BAB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FormerGainContingencyRecognizedInCurrentPeriod" xlink:label="loc_us-gaap_FormerGainContingencyRecognizedInCurrentPeriod_3DD51ECD7255DC7F1C969FB483CC51B2" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_us-gaap_FormerGainContingencyRecognizedInCurrentPeriod_3DD51ECD7255DC7F1C969FB483CC51B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_51EC72430EDCB7DAF2C89FB483CCA258" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_BasisOfPresentationLineItems_FD48E920114C99B5098A9FB483CB3584" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_51EC72430EDCB7DAF2C89FB483CCA258" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/CommitmentsAndContingencies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/CommitmentsAndContingenciesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityInformationLineItems" xlink:label="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntitiesTable" xlink:label="loc_dei_EntitiesTable_0216AA11D9C1A601AB709A494CA2873D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_dei_EntitiesTable_0216AA11D9C1A601AB709A494CA2873D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_BCB23D4658030D9F2D239A494CA35A10" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_0216AA11D9C1A601AB709A494CA2873D" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_BCB23D4658030D9F2D239A494CA35A10" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_DF03AAA8DBFDDE0E06769A494CA3F64D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_BCB23D4658030D9F2D239A494CA35A10" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_DF03AAA8DBFDDE0E06769A494CA3F64D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_DF03AAA8DBFDDE0E06769A494CA3F64D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_BCB23D4658030D9F2D239A494CA35A10" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_DF03AAA8DBFDDE0E06769A494CA3F64D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_21C09EA9602131AC525D9A494CA33C97" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_DF03AAA8DBFDDE0E06769A494CA3F64D" xlink:to="loc_us-gaap_ParentCompanyMember_21C09EA9602131AC525D9A494CA33C97" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_7B79772268272DC770809A494CA28D06" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_0216AA11D9C1A601AB709A494CA2873D" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_7B79772268272DC770809A494CA28D06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C7DE8CD1C346D15D8F769A494CA24234_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_7B79772268272DC770809A494CA28D06" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C7DE8CD1C346D15D8F769A494CA24234_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C7DE8CD1C346D15D8F769A494CA24234" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_7B79772268272DC770809A494CA28D06" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C7DE8CD1C346D15D8F769A494CA24234" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_PathwaysHealthAndCommunitySupportLLCMember" xlink:label="loc_moh_PathwaysHealthAndCommunitySupportLLCMember_0F492CB02F493750A4B29A494CA2CD59" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_C7DE8CD1C346D15D8F769A494CA24234" xlink:to="loc_moh_PathwaysHealthAndCommunitySupportLLCMember_0F492CB02F493750A4B29A494CA2CD59" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_6631E5A74CB80272B5A49AA8DA744F17" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_0216AA11D9C1A601AB709A494CA2873D" xlink:to="loc_dei_LegalEntityAxis_6631E5A74CB80272B5A49AA8DA744F17" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6B8F0E70C73F3E8CACEB9AA8DA7CBA05_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_6631E5A74CB80272B5A49AA8DA744F17" xlink:to="loc_dei_EntityDomain_6B8F0E70C73F3E8CACEB9AA8DA7CBA05_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6B8F0E70C73F3E8CACEB9AA8DA7CBA05" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_6631E5A74CB80272B5A49AA8DA744F17" xlink:to="loc_dei_EntityDomain_6B8F0E70C73F3E8CACEB9AA8DA7CBA05" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_RutherfordCountyTennesseeMember" xlink:label="loc_moh_RutherfordCountyTennesseeMember_EADD7A5F5B0938BC70F99AA9911D9FB2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6B8F0E70C73F3E8CACEB9AA8DA7CBA05" xlink:to="loc_moh_RutherfordCountyTennesseeMember_EADD7A5F5B0938BC70F99AA9911D9FB2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LitigationCaseAxis" xlink:label="loc_us-gaap_LitigationCaseAxis_F93D8BF37C1DF64B582B9A494CA24F68" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_0216AA11D9C1A601AB709A494CA2873D" xlink:to="loc_us-gaap_LitigationCaseAxis_F93D8BF37C1DF64B582B9A494CA24F68" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LitigationCaseTypeDomain" xlink:label="loc_us-gaap_LitigationCaseTypeDomain_25F5432DDA537663570C9A494CA2A05F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationCaseAxis_F93D8BF37C1DF64B582B9A494CA24F68" xlink:to="loc_us-gaap_LitigationCaseTypeDomain_25F5432DDA537663570C9A494CA2A05F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LitigationCaseTypeDomain" xlink:label="loc_us-gaap_LitigationCaseTypeDomain_25F5432DDA537663570C9A494CA2A05F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationCaseAxis_F93D8BF37C1DF64B582B9A494CA24F68" xlink:to="loc_us-gaap_LitigationCaseTypeDomain_25F5432DDA537663570C9A494CA2A05F" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_TheRodriquezLitigationMember" xlink:label="loc_moh_TheRodriquezLitigationMember_8F47CF6498F4F22C5FDA9A494CA234B4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LitigationCaseTypeDomain_25F5432DDA537663570C9A494CA2A05F" xlink:to="loc_moh_TheRodriquezLitigationMember_8F47CF6498F4F22C5FDA9A494CA234B4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_6D5BC6846900C9C0AD509A494CA35F46" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_0216AA11D9C1A601AB709A494CA2873D" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_6D5BC6846900C9C0AD509A494CA35F46" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_E5D81C39D19BD366FEA69A494CA38081_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_6D5BC6846900C9C0AD509A494CA35F46" xlink:to="loc_us-gaap_SegmentDomain_E5D81C39D19BD366FEA69A494CA38081_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_E5D81C39D19BD366FEA69A494CA38081" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_6D5BC6846900C9C0AD509A494CA35F46" xlink:to="loc_us-gaap_SegmentDomain_E5D81C39D19BD366FEA69A494CA38081" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_HealthPlansMember" xlink:label="loc_moh_HealthPlansMember_9F85244CA24255DF30799A494CA3A22A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_E5D81C39D19BD366FEA69A494CA38081" xlink:to="loc_moh_HealthPlansMember_9F85244CA24255DF30799A494CA3A22A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_89E0F34B1B04FF57F1EF9A494CA3DD68" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_0216AA11D9C1A601AB709A494CA2873D" xlink:to="loc_us-gaap_StatementGeographicalAxis_89E0F34B1B04FF57F1EF9A494CA3DD68" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_911F555D9B2520F24CDC9A494CA3A4E2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_89E0F34B1B04FF57F1EF9A494CA3DD68" xlink:to="loc_us-gaap_SegmentGeographicalDomain_911F555D9B2520F24CDC9A494CA3A4E2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_911F555D9B2520F24CDC9A494CA3A4E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementGeographicalAxis_89E0F34B1B04FF57F1EF9A494CA3DD68" xlink:to="loc_us-gaap_SegmentGeographicalDomain_911F555D9B2520F24CDC9A494CA3A4E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/stpr/2011/stpr-2011-01-31.xsd#stpr_IL" xlink:label="loc_stpr_IL_A65ED2FF242C3CF024D49A494CA356B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_911F555D9B2520F24CDC9A494CA3A4E2" xlink:to="loc_stpr_IL_A65ED2FF242C3CF024D49A494CA356B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_PR" xlink:label="loc_country_PR_2C71B1314275F8D4EF9C9A494CA37A74" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_911F555D9B2520F24CDC9A494CA3A4E2" xlink:to="loc_country_PR_2C71B1314275F8D4EF9C9A494CA37A74" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_5B4672F4DC8E579FDC429A494CA328A7" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_0216AA11D9C1A601AB709A494CA2873D" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_5B4672F4DC8E579FDC429A494CA328A7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_709772448200A26C74C39A494CA38FB6_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_5B4672F4DC8E579FDC429A494CA328A7" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_709772448200A26C74C39A494CA38FB6_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_709772448200A26C74C39A494CA38FB6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_5B4672F4DC8E579FDC429A494CA328A7" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_709772448200A26C74C39A494CA38FB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember_3953E15A940C5CE4A12C9A494CA3F70B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_709772448200A26C74C39A494CA38FB6" xlink:to="loc_us-gaap_SubsequentEventMember_3953E15A940C5CE4A12C9A494CA3F70B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AmountOfRestrictedNetAssetsForConsolidatedAndUnconsolidatedSubsidiaries" xlink:label="loc_us-gaap_AmountOfRestrictedNetAssetsForConsolidatedAndUnconsolidatedSubsidiaries_241EA33BB5826F3D6BF59A494CA30AE8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_us-gaap_AmountOfRestrictedNetAssetsForConsolidatedAndUnconsolidatedSubsidiaries_241EA33BB5826F3D6BF59A494CA30AE8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndInvestmentsCurrent" xlink:label="loc_us-gaap_RestrictedCashAndInvestmentsCurrent_97663EC8BC52339798BD9A494CA42BBC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_us-gaap_RestrictedCashAndInvestmentsCurrent_97663EC8BC52339798BD9A494CA42BBC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance" xlink:label="loc_us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance_305EF961F8144A501D629A494CA44035" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance_305EF961F8144A501D629A494CA44035" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusRequired" xlink:label="loc_us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusRequired_31132BEAA68E4F824DFF9A494CA4D70B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusRequired_31132BEAA68E4F824DFF9A494CA4D70B" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_AffordableCareActPremiumStabilizationProgramRiskCorridorReceivableNotRecognizedPriorYears" xlink:label="loc_moh_AffordableCareActPremiumStabilizationProgramRiskCorridorReceivableNotRecognizedPriorYears_9A9F7FE48A51AA052D8D9A494CA431DC" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_moh_AffordableCareActPremiumStabilizationProgramRiskCorridorReceivableNotRecognizedPriorYears_9A9F7FE48A51AA052D8D9A494CA431DC" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_AffordableCareActPremiumStabilizationProgramRiskCorridorReceivableNotRecognizedCurrentYear" xlink:label="loc_moh_AffordableCareActPremiumStabilizationProgramRiskCorridorReceivableNotRecognizedCurrentYear_A82ECBCDD1FDF25E620D9A494CA47343" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_moh_AffordableCareActPremiumStabilizationProgramRiskCorridorReceivableNotRecognizedCurrentYear_A82ECBCDD1FDF25E620D9A494CA47343" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingencyNumberOfPlaintiffs" xlink:label="loc_us-gaap_LossContingencyNumberOfPlaintiffs_E5DDDA12BF7D7C9A7A169A494CA4F68E" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_us-gaap_LossContingencyNumberOfPlaintiffs_E5DDDA12BF7D7C9A7A169A494CA4F68E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized" xlink:label="loc_us-gaap_BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized_87C57CF5C95111E2DF6B9A494CA46368" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_us-gaap_BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized_87C57CF5C95111E2DF6B9A494CA46368" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LossContingencyDamagesAwardedValue" xlink:label="loc_us-gaap_LossContingencyDamagesAwardedValue_DEF2D34D801CEDC8140F9AA7C3ACC2A8" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_us-gaap_LossContingencyDamagesAwardedValue_DEF2D34D801CEDC8140F9AA7C3ACC2A8" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_HealthCareOrganizationNumberOfMembers" xlink:label="loc_moh_HealthCareOrganizationNumberOfMembers_256CF5BF7D37B491A47E9A494CA40C94" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_moh_HealthCareOrganizationNumberOfMembers_256CF5BF7D37B491A47E9A494CA40C94" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_HealthCareOrganizationPremiumRevenue" xlink:label="loc_us-gaap_HealthCareOrganizationPremiumRevenue_0C8882F083FBE656C7409A494CA49FDB" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_us-gaap_HealthCareOrganizationPremiumRevenue_0C8882F083FBE656C7409A494CA49FDB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReceivablesNetCurrent" xlink:label="loc_us-gaap_ReceivablesNetCurrent_091B6805A3F5A16429249A494CA4B8B3" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_4F317625577D596CF5779A494CA3269B" xlink:to="loc_us-gaap_ReceivablesNetCurrent_091B6805A3F5A16429249A494CA4B8B3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ConsolidatedBalanceSheets" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ConsolidatedStatementsOfCashFlows" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_B77AF2B8D7BF75DD75A5A06493C24794" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_5E16F3AF79673DE0287AA06493C1C69B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_B77AF2B8D7BF75DD75A5A06493C24794" xlink:to="loc_us-gaap_StatementTable_5E16F3AF79673DE0287AA06493C1C69B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_8F082678AA149C34B725A06493C21C89" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_5E16F3AF79673DE0287AA06493C1C69B" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_8F082678AA149C34B725A06493C21C89" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_B3E6FD797A66128D69EBA06493C2C88B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_8F082678AA149C34B725A06493C21C89" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_B3E6FD797A66128D69EBA06493C2C88B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_B3E6FD797A66128D69EBA06493C2C88B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_8F082678AA149C34B725A06493C21C89" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_B3E6FD797A66128D69EBA06493C2C88B" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CallOptionDerivativeAssetMember" xlink:label="loc_moh_CallOptionDerivativeAssetMember_9A4A247A276DF4BB8A8DA06493C2539B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_B3E6FD797A66128D69EBA06493C2C88B" xlink:to="loc_moh_CallOptionDerivativeAssetMember_9A4A247A276DF4BB8A8DA06493C2539B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmbeddedDerivativeFinancialInstrumentsMember" xlink:label="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_AC9186EB2CEFCFC9ADE3A06493C2F9CC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_B3E6FD797A66128D69EBA06493C2C88B" xlink:to="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_AC9186EB2CEFCFC9ADE3A06493C2F9CC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_E3F626244FAC19403880A06493C736A8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B77AF2B8D7BF75DD75A5A06493C24794" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_E3F626244FAC19403880A06493C736A8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_A13358B86A1259824BE5A06493C7217F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_E3F626244FAC19403880A06493C736A8" xlink:to="loc_us-gaap_NetIncomeLoss_A13358B86A1259824BE5A06493C7217F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6BEC1366C18CA6884E95A06493C731F3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_E3F626244FAC19403880A06493C736A8" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6BEC1366C18CA6884E95A06493C731F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_0ECE333858E03130E9A6A06493C8B2F9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6BEC1366C18CA6884E95A06493C731F3" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_0ECE333858E03130E9A6A06493C8B2F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetImpairment" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetImpairment_824198D0BA3A010B1EDFA06493C8D239" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6BEC1366C18CA6884E95A06493C731F3" xlink:to="loc_us-gaap_GoodwillAndIntangibleAssetImpairment_824198D0BA3A010B1EDFA06493C8D239" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredIncomeTaxes" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_A654DE90CD5F5B4E3CB5A06493C8431F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6BEC1366C18CA6884E95A06493C731F3" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredIncomeTaxes_A654DE90CD5F5B4E3CB5A06493C8431F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_FB8607CBA6C6A4DE902EA06493C8789A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6BEC1366C18CA6884E95A06493C731F3" xlink:to="loc_us-gaap_ShareBasedCompensation_FB8607CBA6C6A4DE902EA06493C8789A" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_AmortizationOfDebtDiscountPremiumAndSaleLeasebackFinancingObligation" xlink:label="loc_moh_AmortizationOfDebtDiscountPremiumAndSaleLeasebackFinancingObligation_1C7CB85ACA56FC0C6E19A06493C8F992" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6BEC1366C18CA6884E95A06493C731F3" xlink:to="loc_moh_AmortizationOfDebtDiscountPremiumAndSaleLeasebackFinancingObligation_1C7CB85ACA56FC0C6E19A06493C8F992" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherOperatingActivitiesCashFlowStatement" xlink:label="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_93AE98E9AEDF6C71C093A06493C8810E" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_6BEC1366C18CA6884E95A06493C731F3" xlink:to="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_93AE98E9AEDF6C71C093A06493C8810E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3323AC95E3CD9E427230A06493C84550" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_E3F626244FAC19403880A06493C736A8" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3323AC95E3CD9E427230A06493C84550" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInReceivables" xlink:label="loc_us-gaap_IncreaseDecreaseInReceivables_A4A700D4F33BE30577E2A06493C844A5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3323AC95E3CD9E427230A06493C84550" xlink:to="loc_us-gaap_IncreaseDecreaseInReceivables_A4A700D4F33BE30577E2A06493C844A5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_F5CF0BFEF84E88E79A3DA06493C8F9AE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3323AC95E3CD9E427230A06493C84550" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_F5CF0BFEF84E88E79A3DA06493C8F9AE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInHealthCareInsuranceLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInHealthCareInsuranceLiabilities_CF58913B2259ACAA1D2FA06493C8DF60" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3323AC95E3CD9E427230A06493C84550" xlink:to="loc_us-gaap_IncreaseDecreaseInHealthCareInsuranceLiabilities_CF58913B2259ACAA1D2FA06493C8DF60" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_IncreaseDecreaseInMedicalPremiumLiabilityDueToAgency" xlink:label="loc_moh_IncreaseDecreaseInMedicalPremiumLiabilityDueToAgency_5784FF74DAAAD84024F3A06493C8D3DD" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3323AC95E3CD9E427230A06493C84550" xlink:to="loc_moh_IncreaseDecreaseInMedicalPremiumLiabilityDueToAgency_5784FF74DAAAD84024F3A06493C8D3DD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_31EF0CD177B6CE996CC9A06493C8F28B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3323AC95E3CD9E427230A06493C84550" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_31EF0CD177B6CE996CC9A06493C8F28B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_E1DA0EB90CD34030560DA06493C86EC0" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3323AC95E3CD9E427230A06493C84550" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_E1DA0EB90CD34030560DA06493C86EC0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_1F2B4AEC56A8570DCF97A06493C8F9E7" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_3323AC95E3CD9E427230A06493C84550" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_1F2B4AEC56A8570DCF97A06493C8F9E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_014B9479BC9A9BD4664CA06493C9E730" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_E3F626244FAC19403880A06493C736A8" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_014B9479BC9A9BD4664CA06493C9E730" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_39B29DBA79BDBE1950D3A06493C9AB6F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B77AF2B8D7BF75DD75A5A06493C24794" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_39B29DBA79BDBE1950D3A06493C9AB6F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireMarketableSecurities" xlink:label="loc_us-gaap_PaymentsToAcquireMarketableSecurities_3535D9E866505A7BD5E2A06493C9A1FB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_39B29DBA79BDBE1950D3A06493C9AB6F" xlink:to="loc_us-gaap_PaymentsToAcquireMarketableSecurities_3535D9E866505A7BD5E2A06493C9A1FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities" xlink:label="loc_us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_CC287589F4C82B7C9841A06493C9CD27" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_39B29DBA79BDBE1950D3A06493C9AB6F" xlink:to="loc_us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_CC287589F4C82B7C9841A06493C9CD27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_3BCF9967349DC3DD4EACA06493C92BFC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_39B29DBA79BDBE1950D3A06493C9AB6F" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_3BCF9967349DC3DD4EACA06493C92BFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseOfRestrictedInvestments" xlink:label="loc_us-gaap_IncreaseDecreaseOfRestrictedInvestments_ACD410E8A1F28028326FA06493C92604" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_39B29DBA79BDBE1950D3A06493C9AB6F" xlink:to="loc_us-gaap_IncreaseDecreaseOfRestrictedInvestments_ACD410E8A1F28028326FA06493C92604" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_4A57C97E721886923174A06493C9371A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_39B29DBA79BDBE1950D3A06493C9AB6F" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_4A57C97E721886923174A06493C9371A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_D06B208D597A9A4EA449A06493C92350" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_39B29DBA79BDBE1950D3A06493C9AB6F" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_D06B208D597A9A4EA449A06493C92350" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_F647BD4EE64855AE8B83A06493C9D659" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_39B29DBA79BDBE1950D3A06493C9AB6F" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_F647BD4EE64855AE8B83A06493C9D659" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_EAA5060361B420AC28EBA06493C931A6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B77AF2B8D7BF75DD75A5A06493C24794" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_EAA5060361B420AC28EBA06493C931A6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromDebtNetOfIssuanceCosts" xlink:label="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_8122254F00FE2AD8BC13A06493C935DF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_EAA5060361B420AC28EBA06493C931A6" xlink:to="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_8122254F00FE2AD8BC13A06493C935DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_864F5D8388CE8E98C130A06493C98753" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_EAA5060361B420AC28EBA06493C931A6" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_864F5D8388CE8E98C130A06493C98753" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" xlink:label="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_9422C13300B18CD0B31DA06493C9C95B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_EAA5060361B420AC28EBA06493C931A6" xlink:to="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_9422C13300B18CD0B31DA06493C9C95B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_8E38A6B4521ACF813240A06493C999A9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_EAA5060361B420AC28EBA06493C931A6" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_8E38A6B4521ACF813240A06493C999A9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_47943E102CB6D16D9538A06493C986B5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B77AF2B8D7BF75DD75A5A06493C24794" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_47943E102CB6D16D9538A06493C986B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_41FDBE6CECCCD7311F41A06493CADE17" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B77AF2B8D7BF75DD75A5A06493C24794" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_41FDBE6CECCCD7311F41A06493CADE17" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_85E53298DAEB1EF9AE89A06493CAE433" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_B77AF2B8D7BF75DD75A5A06493C24794" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_85E53298DAEB1EF9AE89A06493CAE433" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:label="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_83B3CB375EC439E96060A06493CA7AB2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_85E53298DAEB1EF9AE89A06493CAE433" xlink:to="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_83B3CB375EC439E96060A06493CA7AB2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockIssued1" xlink:label="loc_us-gaap_StockIssued1_C533EA96D5DA638BFB76A06493CABAA3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_83B3CB375EC439E96060A06493CA7AB2" xlink:to="loc_us-gaap_StockIssued1_C533EA96D5DA638BFB76A06493CABAA3" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_DetailsofchangeinfairvalueofderivativesAbstract" xlink:label="loc_moh_DetailsofchangeinfairvalueofderivativesAbstract_F820CDDDE41CD5A9231FA06493CA860A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_85E53298DAEB1EF9AE89A06493CAE433" xlink:to="loc_moh_DetailsofchangeinfairvalueofderivativesAbstract_F820CDDDE41CD5A9231FA06493CA860A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeGainLossOnDerivativeNet" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet_1D52F5604E029B475EA5A06493CAF76F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_DetailsofchangeinfairvalueofderivativesAbstract_F820CDDDE41CD5A9231FA06493CA860A" xlink:to="loc_us-gaap_DerivativeGainLossOnDerivativeNet_1D52F5604E029B475EA5A06493CAF76F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BusinessCombinationDescriptionAbstract" xlink:label="loc_us-gaap_BusinessCombinationDescriptionAbstract_4185BFF08368D9525199A06493CAEF62" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_85E53298DAEB1EF9AE89A06493CAE433" xlink:to="loc_us-gaap_BusinessCombinationDescriptionAbstract_4185BFF08368D9525199A06493CAEF62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueOfAssetsAcquired" xlink:label="loc_us-gaap_FairValueOfAssetsAcquired_CE14C98C1D98E81733A7A06493CAF81C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationDescriptionAbstract_4185BFF08368D9525199A06493CAEF62" xlink:to="loc_us-gaap_FairValueOfAssetsAcquired_CE14C98C1D98E81733A7A06493CAF81C" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_BusinessCombinationPurchasePriceAmountsAccruedReceived" xlink:label="loc_moh_BusinessCombinationPurchasePriceAmountsAccruedReceived_C9BB588DF26844E511DAA06493CA5FC0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationDescriptionAbstract_4185BFF08368D9525199A06493CAEF62" xlink:to="loc_moh_BusinessCombinationPurchasePriceAmountsAccruedReceived_C9BB588DF26844E511DAA06493CA5FC0" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_BusinessCombinationPrepaidConsiderationTransferred" xlink:label="loc_moh_BusinessCombinationPrepaidConsiderationTransferred_00844536907DBCFCD798A06493CA2A68" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationDescriptionAbstract_4185BFF08368D9525199A06493CAEF62" xlink:to="loc_moh_BusinessCombinationPrepaidConsiderationTransferred_00844536907DBCFCD798A06493CA2A68" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ConsolidatedStatementsOfCashFlowsParenthetical" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_6D4DD1B86A4465D63A8B85D56A13971A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_0C572A2DEF0782598E4885D56A13D81B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_6D4DD1B86A4465D63A8B85D56A13971A" xlink:to="loc_us-gaap_StatementTable_0C572A2DEF0782598E4885D56A13D81B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_2453A08D46596633071D85D56A131528" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0C572A2DEF0782598E4885D56A13D81B" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_2453A08D46596633071D85D56A131528" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_6E5B496770BAECBA8E6D85D56A131E5A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2453A08D46596633071D85D56A131528" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_6E5B496770BAECBA8E6D85D56A131E5A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_6E5B496770BAECBA8E6D85D56A131E5A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_2453A08D46596633071D85D56A131528" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_6E5B496770BAECBA8E6D85D56A131E5A" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CallOptionDerivativeAssetMember" xlink:label="loc_moh_CallOptionDerivativeAssetMember_3E7074474FB2EFF4697A85D56A13007C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_6E5B496770BAECBA8E6D85D56A131E5A" xlink:to="loc_moh_CallOptionDerivativeAssetMember_3E7074474FB2EFF4697A85D56A13007C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmbeddedDerivativeFinancialInstrumentsMember" xlink:label="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_B03F13D6574783423A9E85D56A135A7C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_6E5B496770BAECBA8E6D85D56A131E5A" xlink:to="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_B03F13D6574783423A9E85D56A135A7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFixedInterestRate" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_4415D89B76C99CB5477585D56A13B1B2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6D4DD1B86A4465D63A8B85D56A13971A" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_4415D89B76C99CB5477585D56A13B1B2" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ConsolidatedStatementsOfComprehensiveLossIncome" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ConsolidatedStatementsOfOperations" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/Debt" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/DebtAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_11AC903F179B73856BCF9FB076495CE2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_DebtInstrumentTable_11AC903F179B73856BCF9FB076495CE2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_5C4913B8D63442DBE3D19FB076494791" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_11AC903F179B73856BCF9FB076495CE2" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_5C4913B8D63442DBE3D19FB076494791" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_F16A59C4BDD73B59322A9FB076497D07_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_5C4913B8D63442DBE3D19FB076494791" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_F16A59C4BDD73B59322A9FB076497D07_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_F16A59C4BDD73B59322A9FB076497D07" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_5C4913B8D63442DBE3D19FB076494791" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_F16A59C4BDD73B59322A9FB076497D07" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_54DF7DCE008824C75FFE9FB0764978A2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_F16A59C4BDD73B59322A9FB076497D07" xlink:to="loc_us-gaap_SeniorNotesMember_54DF7DCE008824C75FFE9FB0764978A2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_UnsecuredDebtMember" xlink:label="loc_us-gaap_UnsecuredDebtMember_F0604205A98FF836AA4B9FB076494CE2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_F16A59C4BDD73B59322A9FB076497D07" xlink:to="loc_us-gaap_UnsecuredDebtMember_F0604205A98FF836AA4B9FB076494CE2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConvertibleDebtMember" xlink:label="loc_us-gaap_ConvertibleDebtMember_9B750F4DE9E577C577EF9FB0764995C5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_F16A59C4BDD73B59322A9FB076497D07" xlink:to="loc_us-gaap_ConvertibleDebtMember_9B750F4DE9E577C577EF9FB0764995C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_AE71647EE66200196DAB9FB07649B948" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_11AC903F179B73856BCF9FB076495CE2" xlink:to="loc_us-gaap_CreditFacilityAxis_AE71647EE66200196DAB9FB07649B948" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_250A4A5003B3707C199A9FB076495058_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_AE71647EE66200196DAB9FB07649B948" xlink:to="loc_us-gaap_CreditFacilityDomain_250A4A5003B3707C199A9FB076495058_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_250A4A5003B3707C199A9FB076495058" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_AE71647EE66200196DAB9FB07649B948" xlink:to="loc_us-gaap_CreditFacilityDomain_250A4A5003B3707C199A9FB076495058" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_E2639537CF57DB3EAE939FB0764AEB54" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_250A4A5003B3707C199A9FB076495058" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_E2639537CF57DB3EAE939FB0764AEB54" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LetterOfCreditMember" xlink:label="loc_us-gaap_LetterOfCreditMember_D4D5BCC0F7BA642E0E979FB0764A9EDC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_250A4A5003B3707C199A9FB076495058" xlink:to="loc_us-gaap_LetterOfCreditMember_D4D5BCC0F7BA642E0E979FB0764A9EDC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_02DC701BE448182BCE9A9FB0764AF1BE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_11AC903F179B73856BCF9FB076495CE2" xlink:to="loc_us-gaap_DebtInstrumentAxis_02DC701BE448182BCE9A9FB0764AF1BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_AF9F1FBDEEF75434817D9FB0764A4340_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_02DC701BE448182BCE9A9FB0764AF1BE" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_AF9F1FBDEEF75434817D9FB0764A4340_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_AF9F1FBDEEF75434817D9FB0764A4340" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_02DC701BE448182BCE9A9FB0764AF1BE" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_AF9F1FBDEEF75434817D9FB0764A4340" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_A4.875SeniorNotesMember" xlink:label="loc_moh_A4.875SeniorNotesMember_CE9922E0F348AF6ABFC89FB0764AA4FE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_AF9F1FBDEEF75434817D9FB0764A4340" xlink:to="loc_moh_A4.875SeniorNotesMember_CE9922E0F348AF6ABFC89FB0764AA4FE" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_SeniorNotesDue2022Member" xlink:label="loc_moh_SeniorNotesDue2022Member_19A771D943368EC8771D9FB0764A5C6B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_AF9F1FBDEEF75434817D9FB0764A4340" xlink:to="loc_moh_SeniorNotesDue2022Member_19A771D943368EC8771D9FB0764A5C6B" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CashConvertibleSeniorNotesDue2020Member" xlink:label="loc_moh_CashConvertibleSeniorNotesDue2020Member_EFA8A280F3C62BC070849FB0764A47EE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_AF9F1FBDEEF75434817D9FB0764A4340" xlink:to="loc_moh_CashConvertibleSeniorNotesDue2020Member_EFA8A280F3C62BC070849FB0764A47EE" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ConvertibleSeniorNotesDue2044Member" xlink:label="loc_moh_ConvertibleSeniorNotesDue2044Member_68DFF1D1064CD14EC0339FB0764A33BB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_AF9F1FBDEEF75434817D9FB0764A4340" xlink:to="loc_moh_ConvertibleSeniorNotesDue2044Member_68DFF1D1064CD14EC0339FB0764A33BB" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_DebtCommitmentLetterMember" xlink:label="loc_moh_DebtCommitmentLetterMember_4CAD30D477FD44CFCBDB9FB0764AE1FD" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_AF9F1FBDEEF75434817D9FB0764A4340" xlink:to="loc_moh_DebtCommitmentLetterMember_4CAD30D477FD44CFCBDB9FB0764AE1FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_0D4091B35876862A9EA59FB0764A25DF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_0D4091B35876862A9EA59FB0764A25DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_284381705E0234A21B599FB0764A481D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_284381705E0234A21B599FB0764A481D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_AF68E214E5E7625A07B89FB0764A85ED" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_AF68E214E5E7625A07B89FB0764A85ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_0ECAFB482BD4D334F8A89FB0764AF8A6" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_0ECAFB482BD4D334F8A89FB0764AF8A6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCredit" xlink:label="loc_us-gaap_LineOfCredit_A3337105EBD803E663479FB0764AE7CD" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_LineOfCredit_A3337105EBD803E663479FB0764AE7CD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_667C98ACFB72786DECAE9FB0764AEDAF" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_667C98ACFB72786DECAE9FB0764AEDAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="loc_us-gaap_DebtInstrumentTerm_951D73CF093A715422A39FB0764A1543" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_DebtInstrumentTerm_951D73CF093A715422A39FB0764A1543" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LinesOfCreditCurrent" xlink:label="loc_us-gaap_LinesOfCreditCurrent_13697A8A48CAF211C2259FB0764B58CF" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_LinesOfCreditCurrent_13697A8A48CAF211C2259FB0764B58CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_A37B1C8FD82E580D1C6B9FB0764B18BE" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32FED0C2C39F2E36F6679FB0764A57B9" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_A37B1C8FD82E580D1C6B9FB0764B18BE" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/DebtScheduleOfLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_98C12C5C0FD2357D4B5D8137D8BA9049" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_FECFE70DD5DC4BCF976E8137D8B9D0BB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_98C12C5C0FD2357D4B5D8137D8BA9049" xlink:to="loc_us-gaap_DebtInstrumentTable_FECFE70DD5DC4BCF976E8137D8B9D0BB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_282CCBF205A47F72E7A88137D8B91574" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_FECFE70DD5DC4BCF976E8137D8B9D0BB" xlink:to="loc_us-gaap_DebtInstrumentAxis_282CCBF205A47F72E7A88137D8B91574" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_C286F59279E4755D4B868137D8B9BFA5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_282CCBF205A47F72E7A88137D8B91574" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_C286F59279E4755D4B868137D8B9BFA5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_C286F59279E4755D4B868137D8B9BFA5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_282CCBF205A47F72E7A88137D8B91574" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_C286F59279E4755D4B868137D8B9BFA5" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CashConvertibleSeniorNotesDue2020Member" xlink:label="loc_moh_CashConvertibleSeniorNotesDue2020Member_1F30DDD1E826B8E916AD8137D8B981EC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_C286F59279E4755D4B868137D8B9BFA5" xlink:to="loc_moh_CashConvertibleSeniorNotesDue2020Member_1F30DDD1E826B8E916AD8137D8B981EC" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_SeniorNotesDue2022Member" xlink:label="loc_moh_SeniorNotesDue2022Member_C56F55804B407BEDB0738137D8B99F4E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_C286F59279E4755D4B868137D8B9BFA5" xlink:to="loc_moh_SeniorNotesDue2022Member_C56F55804B407BEDB0738137D8B99F4E" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_A4.875SeniorNotesMember" xlink:label="loc_moh_A4.875SeniorNotesMember_2C8B2ABDC1D0FEAC8AB48137D8BAF31B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_C286F59279E4755D4B868137D8B9BFA5" xlink:to="loc_moh_A4.875SeniorNotesMember_2C8B2ABDC1D0FEAC8AB48137D8BAF31B" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ConvertibleSeniorNotesDue2044Member" xlink:label="loc_moh_ConvertibleSeniorNotesDue2044Member_01D4D2D37EE80FBAB0168137D8BABAD3" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_C286F59279E4755D4B868137D8B9BFA5" xlink:to="loc_moh_ConvertibleSeniorNotesDue2044Member_01D4D2D37EE80FBAB0168137D8BABAD3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_6AEADDFA6A43770A70838137D8BA6F12" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_FECFE70DD5DC4BCF976E8137D8B9D0BB" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_6AEADDFA6A43770A70838137D8BA6F12" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5A2C59F849133265DFB08137D8BAA94F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_6AEADDFA6A43770A70838137D8BA6F12" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5A2C59F849133265DFB08137D8BAA94F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5A2C59F849133265DFB08137D8BAA94F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_6AEADDFA6A43770A70838137D8BA6F12" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5A2C59F849133265DFB08137D8BAA94F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConvertibleDebtMember" xlink:label="loc_us-gaap_ConvertibleDebtMember_3E354C80AFB49BB474BF8137D8BACF7D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5A2C59F849133265DFB08137D8BAA94F" xlink:to="loc_us-gaap_ConvertibleDebtMember_3E354C80AFB49BB474BF8137D8BACF7D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_87868A9FF7A8000FBA718137D8BAA1B5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5A2C59F849133265DFB08137D8BAA94F" xlink:to="loc_us-gaap_SeniorNotesMember_87868A9FF7A8000FBA718137D8BAA1B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtCurrentAbstract" xlink:label="loc_us-gaap_DebtCurrentAbstract_9151E1D04108627FF4888137D8BA5ADD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_98C12C5C0FD2357D4B5D8137D8BA9049" xlink:to="loc_us-gaap_DebtCurrentAbstract_9151E1D04108627FF4888137D8BA5ADD" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_LongTermDebtCurrentMaturitiesNetOfUnamortizedPremiumDiscount" xlink:label="loc_moh_LongTermDebtCurrentMaturitiesNetOfUnamortizedPremiumDiscount_D099C2058C0B30DCFFF58137D8BA5A04" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtCurrentAbstract_9151E1D04108627FF4888137D8BA5ADD" xlink:to="loc_moh_LongTermDebtCurrentMaturitiesNetOfUnamortizedPremiumDiscount_D099C2058C0B30DCFFF58137D8BA5A04" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalLeaseObligationsCurrent" xlink:label="loc_us-gaap_CapitalLeaseObligationsCurrent_B020195CD89D5D5C46FA8137D8BACAAB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtCurrentAbstract_9151E1D04108627FF4888137D8BA5ADD" xlink:to="loc_us-gaap_CapitalLeaseObligationsCurrent_B020195CD89D5D5C46FA8137D8BACAAB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredFinanceCostsCurrentNet" xlink:label="loc_us-gaap_DeferredFinanceCostsCurrentNet_4707890A1E38840E6F808137D8BAC26D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtCurrentAbstract_9151E1D04108627FF4888137D8BA5ADD" xlink:to="loc_us-gaap_DeferredFinanceCostsCurrentNet_4707890A1E38840E6F808137D8BAC26D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_72A1A11B8E83FED4BB8E8137D8BB3524" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtCurrentAbstract_9151E1D04108627FF4888137D8BA5ADD" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_72A1A11B8E83FED4BB8E8137D8BB3524" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtNoncurrentAbstract" xlink:label="loc_us-gaap_LongTermDebtNoncurrentAbstract_12BBCD6354BBFD5237638137D8BB6937" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_98C12C5C0FD2357D4B5D8137D8BA9049" xlink:to="loc_us-gaap_LongTermDebtNoncurrentAbstract_12BBCD6354BBFD5237638137D8BB6937" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_LongTermDebtNoncurrentNetOfUnamortizedDebtDiscount" xlink:label="loc_moh_LongTermDebtNoncurrentNetOfUnamortizedDebtDiscount_8F1E56A9B4B10C066BDC8137D8BB2A60" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtNoncurrentAbstract_12BBCD6354BBFD5237638137D8BB6937" xlink:to="loc_moh_LongTermDebtNoncurrentNetOfUnamortizedDebtDiscount_8F1E56A9B4B10C066BDC8137D8BB2A60" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredFinanceCostsNoncurrentNet" xlink:label="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_02F8723C7BB64BC84D8B8137D8BB64D5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtNoncurrentAbstract_12BBCD6354BBFD5237638137D8BB6937" xlink:to="loc_us-gaap_DeferredFinanceCostsNoncurrentNet_02F8723C7BB64BC84D8B8137D8BB64D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_BDA6C1D1AFDACDCFA41A8137D8BBDD56" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtNoncurrentAbstract_12BBCD6354BBFD5237638137D8BB6937" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_BDA6C1D1AFDACDCFA41A8137D8BBDD56" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CapitalLeaseObligationsNoncurrent" xlink:label="loc_us-gaap_CapitalLeaseObligationsNoncurrent_D30D0AB383AF90006C068137D8BBEF68" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_98C12C5C0FD2357D4B5D8137D8BA9049" xlink:to="loc_us-gaap_CapitalLeaseObligationsNoncurrent_D30D0AB383AF90006C068137D8BBEF68" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities_F0AB5D1CE774706D0B088137D8BBCE94" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_98C12C5C0FD2357D4B5D8137D8BA9049" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities_F0AB5D1CE774706D0B088137D8BBCE94" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_824E4F1C3DB1B0D9FD418137D8BB77CA" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_98C12C5C0FD2357D4B5D8137D8BA9049" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_824E4F1C3DB1B0D9FD418137D8BB77CA" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/DebtTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/Derivatives" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/DerivativesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="loc_us-gaap_DerivativeLineItems_42CE501CBE3BD5A1BEBF8137D8A16D6E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeTable" xlink:label="loc_us-gaap_DerivativeTable_83DDF4BB69EA6B2D14D88137D8A1D7AE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_42CE501CBE3BD5A1BEBF8137D8A16D6E" xlink:to="loc_us-gaap_DerivativeTable_83DDF4BB69EA6B2D14D88137D8A1D7AE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_3EA3F199F51E6FDFA0AD8137D8A1CBC1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_83DDF4BB69EA6B2D14D88137D8A1D7AE" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_3EA3F199F51E6FDFA0AD8137D8A1CBC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_4A09A5B1A7667ED7F2F68137D8A14B6B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_3EA3F199F51E6FDFA0AD8137D8A1CBC1" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_4A09A5B1A7667ED7F2F68137D8A14B6B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_4A09A5B1A7667ED7F2F68137D8A14B6B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_3EA3F199F51E6FDFA0AD8137D8A1CBC1" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_4A09A5B1A7667ED7F2F68137D8A14B6B" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CurrentAssetsMember" xlink:label="loc_moh_CurrentAssetsMember_96C4B15E5F616753D7E68137D8A1AA4F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_4A09A5B1A7667ED7F2F68137D8A14B6B" xlink:to="loc_moh_CurrentAssetsMember_96C4B15E5F616753D7E68137D8A1AA4F" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CurrentLiabilitiesMember" xlink:label="loc_moh_CurrentLiabilitiesMember_8D20FB980D0021F7E71D8137D8A13789" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_4A09A5B1A7667ED7F2F68137D8A14B6B" xlink:to="loc_moh_CurrentLiabilitiesMember_8D20FB980D0021F7E71D8137D8A13789" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_4F861DDABB6799B211598137D8A1836D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_83DDF4BB69EA6B2D14D88137D8A1D7AE" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_4F861DDABB6799B211598137D8A1836D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_958AAF2D9BB8B965971C8137D8A1E260_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4F861DDABB6799B211598137D8A1836D" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_958AAF2D9BB8B965971C8137D8A1E260_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_958AAF2D9BB8B965971C8137D8A1E260" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4F861DDABB6799B211598137D8A1836D" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_958AAF2D9BB8B965971C8137D8A1E260" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CallOptionDerivativeAssetMember" xlink:label="loc_moh_CallOptionDerivativeAssetMember_635FB419873E21961F768137D8A1E8E1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_958AAF2D9BB8B965971C8137D8A1E260" xlink:to="loc_moh_CallOptionDerivativeAssetMember_635FB419873E21961F768137D8A1E8E1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmbeddedDerivativeFinancialInstrumentsMember" xlink:label="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_B7FD1D8CBCCADF4E315B8137D8A1AD6A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_958AAF2D9BB8B965971C8137D8A1E260" xlink:to="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_B7FD1D8CBCCADF4E315B8137D8A1AD6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_1C56CA90BA3C7776C5D88137D8A136FE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_83DDF4BB69EA6B2D14D88137D8A1D7AE" xlink:to="loc_us-gaap_DebtInstrumentAxis_1C56CA90BA3C7776C5D88137D8A136FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_A1186B515719954A4B1E8137D8A126E9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_1C56CA90BA3C7776C5D88137D8A136FE" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_A1186B515719954A4B1E8137D8A126E9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_A1186B515719954A4B1E8137D8A126E9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_1C56CA90BA3C7776C5D88137D8A136FE" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_A1186B515719954A4B1E8137D8A126E9" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CashConvertibleSeniorNotesDue2020Member" xlink:label="loc_moh_CashConvertibleSeniorNotesDue2020Member_8BD83105C4B04CE59BC98137D8A18528" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_A1186B515719954A4B1E8137D8A126E9" xlink:to="loc_moh_CashConvertibleSeniorNotesDue2020Member_8BD83105C4B04CE59BC98137D8A18528" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_9505906B20470EB497AE8137D8A209DF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_42CE501CBE3BD5A1BEBF8137D8A16D6E" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_9505906B20470EB497AE8137D8A209DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_3B0748403012D02171078137D8A2FD06" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_42CE501CBE3BD5A1BEBF8137D8A16D6E" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_3B0748403012D02171078137D8A2FD06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFixedInterestRate" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_7F8C479B9EF7AA50C8338137D8A2D438" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_42CE501CBE3BD5A1BEBF8137D8A16D6E" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_7F8C479B9EF7AA50C8338137D8A2D438" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_50BDC787BFE4383B0E538137D8A29BC0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_42CE501CBE3BD5A1BEBF8137D8A16D6E" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_50BDC787BFE4383B0E538137D8A29BC0" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/DerivativesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/DocumentAndEntityInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/FairValueMeasurements" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/FairValueMeasurementsDetailsOfLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_970531959E26CE42E02E862034E22285" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6D0CBDC578598ECBCC43862034E17EC2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_970531959E26CE42E02E862034E22285" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6D0CBDC578598ECBCC43862034E17EC2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_0A1DB28ED1762F4AB701862034E1768F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6D0CBDC578598ECBCC43862034E17EC2" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_0A1DB28ED1762F4AB701862034E1768F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_D814BCD6E20EAE62E66E862034E1C149_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_0A1DB28ED1762F4AB701862034E1768F" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_D814BCD6E20EAE62E66E862034E1C149_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_82A62E63796CB5595374862034E1E611" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_0A1DB28ED1762F4AB701862034E1768F" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_82A62E63796CB5595374862034E1E611" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_D814BCD6E20EAE62E66E862034E1C149" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_82A62E63796CB5595374862034E1E611" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_D814BCD6E20EAE62E66E862034E1C149" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_C9B54C3DDAD929F52CA0862034E136E0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_82A62E63796CB5595374862034E1E611" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_C9B54C3DDAD929F52CA0862034E136E0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_4BDF5779CBDBCC0BE055862034E18D11" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_82A62E63796CB5595374862034E1E611" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_4BDF5779CBDBCC0BE055862034E18D11" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_1CD2EA72FE727C10ADEE862034E1B650" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6D0CBDC578598ECBCC43862034E17EC2" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_1CD2EA72FE727C10ADEE862034E1B650" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_6EDA47CCF26D15E49806862034E1920E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_1CD2EA72FE727C10ADEE862034E1B650" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_6EDA47CCF26D15E49806862034E1920E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_6EDA47CCF26D15E49806862034E1920E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_1CD2EA72FE727C10ADEE862034E1B650" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_6EDA47CCF26D15E49806862034E1920E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_1920712AFAD42B02DB3C862034E10701" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_6EDA47CCF26D15E49806862034E1920E" xlink:to="loc_us-gaap_SeniorNotesMember_1920712AFAD42B02DB3C862034E10701" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConvertibleDebtMember" xlink:label="loc_us-gaap_ConvertibleDebtMember_BE572932AE46004693CA862034E2C7BE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_6EDA47CCF26D15E49806862034E1920E" xlink:to="loc_us-gaap_ConvertibleDebtMember_BE572932AE46004693CA862034E2C7BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_A8DD5DCDEB347CBCED02862034E29F85" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_6D0CBDC578598ECBCC43862034E17EC2" xlink:to="loc_us-gaap_DebtInstrumentAxis_A8DD5DCDEB347CBCED02862034E29F85" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_51BCD9CB7E8CA8C4D42D862034E2CA98_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_A8DD5DCDEB347CBCED02862034E29F85" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_51BCD9CB7E8CA8C4D42D862034E2CA98_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_51BCD9CB7E8CA8C4D42D862034E2CA98" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_A8DD5DCDEB347CBCED02862034E29F85" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_51BCD9CB7E8CA8C4D42D862034E2CA98" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_SeniorNotesDue2022Member" xlink:label="loc_moh_SeniorNotesDue2022Member_2303B88199FCEE2CFBFF862034E2DF7B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_51BCD9CB7E8CA8C4D42D862034E2CA98" xlink:to="loc_moh_SeniorNotesDue2022Member_2303B88199FCEE2CFBFF862034E2DF7B" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CashConvertibleSeniorNotesDue2020Member" xlink:label="loc_moh_CashConvertibleSeniorNotesDue2020Member_E7104B3807E9A1E603CC862034E20384" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_51BCD9CB7E8CA8C4D42D862034E2CA98" xlink:to="loc_moh_CashConvertibleSeniorNotesDue2020Member_E7104B3807E9A1E603CC862034E20384" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_A4.875SeniorNotesMember" xlink:label="loc_moh_A4.875SeniorNotesMember_74BBA1F4D7D24021100A862034E294BE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_51BCD9CB7E8CA8C4D42D862034E2CA98" xlink:to="loc_moh_A4.875SeniorNotesMember_74BBA1F4D7D24021100A862034E294BE" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ConvertibleSeniorNotesDue2044Member" xlink:label="loc_moh_ConvertibleSeniorNotesDue2044Member_96F27B9DF2865C8AEDFE862034E29515" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_51BCD9CB7E8CA8C4D42D862034E2CA98" xlink:to="loc_moh_ConvertibleSeniorNotesDue2044Member_96F27B9DF2865C8AEDFE862034E29515" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_2C2218049537FC201C43862034E2CC04" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_970531959E26CE42E02E862034E22285" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_2C2218049537FC201C43862034E2CC04" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentFairValue" xlink:label="loc_us-gaap_DebtInstrumentFairValue_C762A785468887516DC4862034E29C97" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_970531959E26CE42E02E862034E22285" xlink:to="loc_us-gaap_DebtInstrumentFairValue_C762A785468887516DC4862034E29C97" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/FairValueMeasurementsFairValueOfFinancialInstrumentsOnRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_D4BE022D0EAC48ACF6108137D907DA6A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4676AB79747515D7DD268137D904982D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_D4BE022D0EAC48ACF6108137D907DA6A" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4676AB79747515D7DD268137D904982D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_CB1EF8FE05C1194326268137D90483DA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4676AB79747515D7DD268137D904982D" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_CB1EF8FE05C1194326268137D90483DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_10974C7700599A180ACC8137D905A3ED_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_CB1EF8FE05C1194326268137D90483DA" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_10974C7700599A180ACC8137D905A3ED_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_10974C7700599A180ACC8137D905A3ED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_CB1EF8FE05C1194326268137D90483DA" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_10974C7700599A180ACC8137D905A3ED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_96C3FE61EECEBBB51DF08137D905887F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_10974C7700599A180ACC8137D905A3ED" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_96C3FE61EECEBBB51DF08137D905887F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_70EACCC0D0C62EFC4D0C8137D905EDA8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4676AB79747515D7DD268137D904982D" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_70EACCC0D0C62EFC4D0C8137D905EDA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_31F044FBDC06E3B674D38137D9057B39_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_70EACCC0D0C62EFC4D0C8137D905EDA8" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_31F044FBDC06E3B674D38137D9057B39_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_31F044FBDC06E3B674D38137D9057B39" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_70EACCC0D0C62EFC4D0C8137D905EDA8" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_31F044FBDC06E3B674D38137D9057B39" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_E38C2B8171FA880EB43A8137D9059E71" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_31F044FBDC06E3B674D38137D9057B39" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_E38C2B8171FA880EB43A8137D9059E71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_D1ACA32704BE56025B508137D9052E03" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_31F044FBDC06E3B674D38137D9057B39" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_D1ACA32704BE56025B508137D9052E03" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_8177A408ABE90A6E978B8137D905BD6D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_31F044FBDC06E3B674D38137D9057B39" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_8177A408ABE90A6E978B8137D905BD6D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_D7E0B00A8F3D4F87D7FE8137D905D2A3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4676AB79747515D7DD268137D904982D" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_D7E0B00A8F3D4F87D7FE8137D905D2A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_705E71E1F9451A5C51398137D9056D25_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_D7E0B00A8F3D4F87D7FE8137D905D2A3" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_705E71E1F9451A5C51398137D9056D25_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_705E71E1F9451A5C51398137D9056D25" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_D7E0B00A8F3D4F87D7FE8137D905D2A3" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_705E71E1F9451A5C51398137D9056D25" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CallOptionDerivativeAssetMember" xlink:label="loc_moh_CallOptionDerivativeAssetMember_2A1749132515B7708BAF8137D90540A3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_705E71E1F9451A5C51398137D9056D25" xlink:to="loc_moh_CallOptionDerivativeAssetMember_2A1749132515B7708BAF8137D90540A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmbeddedDerivativeFinancialInstrumentsMember" xlink:label="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_2E86517AB476B77D025C8137D90510E3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_705E71E1F9451A5C51398137D9056D25" xlink:to="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_2E86517AB476B77D025C8137D90510E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis_7115BED274F24ACD7C2D8137D905D255" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4676AB79747515D7DD268137D904982D" xlink:to="loc_us-gaap_FinancialInstrumentAxis_7115BED274F24ACD7C2D8137D905D255" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_7115BED274F24ACD7C2D8137D905D255" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_7115BED274F24ACD7C2D8137D905D255" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_DE92D3D9494FF8B85F478137D906CD9E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_DE92D3D9494FF8B85F478137D906CD9E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_USTreasuryNotesSecuritiesMember" xlink:label="loc_us-gaap_USTreasuryNotesSecuritiesMember_3DA384AD17355601B2118137D906D826" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:to="loc_us-gaap_USTreasuryNotesSecuritiesMember_3DA384AD17355601B2118137D906D826" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_3CB7944A9E0CAB476E8D8137D90655B8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_3CB7944A9E0CAB476E8D8137D90655B8" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MunicipalSecuritiesMember" xlink:label="loc_moh_MunicipalSecuritiesMember_5D23D2D299016900F9798137D906600E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:to="loc_moh_MunicipalSecuritiesMember_5D23D2D299016900F9798137D906600E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetBackedSecuritiesMember" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_C8DCC59E3DA194AEB7FA8137D906BB02" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_C8DCC59E3DA194AEB7FA8137D906BB02" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CertificatesOfDepositMember" xlink:label="loc_us-gaap_CertificatesOfDepositMember_AD4D69BE8CB34CD0D05A8137D906B1A7" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:to="loc_us-gaap_CertificatesOfDepositMember_AD4D69BE8CB34CD0D05A8137D906B1A7" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CurrentInvestmentsMember" xlink:label="loc_moh_CurrentInvestmentsMember_BE20BDDAFAEBAEA38FA78137D9065D89" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:to="loc_moh_CurrentInvestmentsMember_BE20BDDAFAEBAEA38FA78137D9065D89" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFinancialInstrumentsAssetsMember" xlink:label="loc_us-gaap_DerivativeFinancialInstrumentsAssetsMember_4A9D22907DBE3904C3ED8137D906BA9C" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:to="loc_us-gaap_DerivativeFinancialInstrumentsAssetsMember_4A9D22907DBE3904C3ED8137D906BA9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmbeddedDerivativeFinancialInstrumentsMember" xlink:label="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_2BC599A5AF57BF5D42F38137D9060B3E" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8131B7CBF434E147F8498137D905CCB9" xlink:to="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_2BC599A5AF57BF5D42F38137D9060B3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_18340FD4DE84DD7A55CE8137D90622E8" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_4676AB79747515D7DD268137D904982D" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_18340FD4DE84DD7A55CE8137D90622E8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_9BA870D4523899640F3A8137D9068739_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_18340FD4DE84DD7A55CE8137D90622E8" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_9BA870D4523899640F3A8137D9068739_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_9BA870D4523899640F3A8137D9068739" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_18340FD4DE84DD7A55CE8137D90622E8" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_9BA870D4523899640F3A8137D9068739" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_809C09B9DD6EA164761D8137D906FB7A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_9BA870D4523899640F3A8137D9068739" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_809C09B9DD6EA164761D8137D906FB7A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_040659FDCA385651B27C8137D907D7A1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_9BA870D4523899640F3A8137D9068739" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_040659FDCA385651B27C8137D907D7A1" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_RestrictedInvestmentsCurrentMember" xlink:label="loc_moh_RestrictedInvestmentsCurrentMember_E7EB77A1CA4661DD0FAB8137D907430F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_9BA870D4523899640F3A8137D9068739" xlink:to="loc_moh_RestrictedInvestmentsCurrentMember_E7EB77A1CA4661DD0FAB8137D907430F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_0ED8E4FBE9138DB65AE88137D907D3DA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_D4BE022D0EAC48ACF6108137D907DA6A" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_0ED8E4FBE9138DB65AE88137D907D3DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="loc_us-gaap_DerivativeLiabilities_385BF0BC1C600D3EC7C28137D90765F7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_D4BE022D0EAC48ACF6108137D907DA6A" xlink:to="loc_us-gaap_DerivativeLiabilities_385BF0BC1C600D3EC7C28137D90765F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_A64EBE6EC103570D5D618137D907922C" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_D4BE022D0EAC48ACF6108137D907DA6A" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_A64EBE6EC103570D5D618137D907922C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeFixedInterestRate" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_0B65080912FC79DB6D938137D9078EC7" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_D4BE022D0EAC48ACF6108137D907DA6A" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_0B65080912FC79DB6D938137D9078EC7" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/FairValueMeasurementsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ImpairmentLosses" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ImpairmentLossesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_2ABD85DB7BF801DFE3A2A0412D8C9D2B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_646C94BD97CFE8D4EECCA0412D8C7AC3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_2ABD85DB7BF801DFE3A2A0412D8C9D2B" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_646C94BD97CFE8D4EECCA0412D8C7AC3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_76BF6CE0341D3AECBAF0A0412D8C253D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_646C94BD97CFE8D4EECCA0412D8C7AC3" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_76BF6CE0341D3AECBAF0A0412D8C253D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_16DDA253E174CDC061E0A0412D8CE607_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_76BF6CE0341D3AECBAF0A0412D8C253D" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_16DDA253E174CDC061E0A0412D8CE607_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_16DDA253E174CDC061E0A0412D8CE607" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_76BF6CE0341D3AECBAF0A0412D8C253D" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_16DDA253E174CDC061E0A0412D8CE607" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SubsidiariesMember" xlink:label="loc_us-gaap_SubsidiariesMember_9AEAA5EA6AA1560D8D0FA0412D8CB981" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_16DDA253E174CDC061E0A0412D8CE607" xlink:to="loc_us-gaap_SubsidiariesMember_9AEAA5EA6AA1560D8D0FA0412D8CB981" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipAxis" xlink:label="loc_us-gaap_OwnershipAxis_EEB7DFB00C4622C8655DA0412D8CFB6B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_646C94BD97CFE8D4EECCA0412D8C7AC3" xlink:to="loc_us-gaap_OwnershipAxis_EEB7DFB00C4622C8655DA0412D8CFB6B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_0F71C773B7C6932FF5BCA0412D8C8C1A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OwnershipAxis_EEB7DFB00C4622C8655DA0412D8CFB6B" xlink:to="loc_us-gaap_OwnershipDomain_0F71C773B7C6932FF5BCA0412D8C8C1A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OwnershipDomain" xlink:label="loc_us-gaap_OwnershipDomain_0F71C773B7C6932FF5BCA0412D8C8C1A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OwnershipAxis_EEB7DFB00C4622C8655DA0412D8CFB6B" xlink:to="loc_us-gaap_OwnershipDomain_0F71C773B7C6932FF5BCA0412D8C8C1A" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_PathwaysHealthAndCommunitySupportLLCMember" xlink:label="loc_moh_PathwaysHealthAndCommunitySupportLLCMember_A2EF82FF016D2764489CA0412D8C6FD0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OwnershipDomain_0F71C773B7C6932FF5BCA0412D8C8C1A" xlink:to="loc_moh_PathwaysHealthAndCommunitySupportLLCMember_A2EF82FF016D2764489CA0412D8C6FD0" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_OtherSubsidiaryMember" xlink:label="loc_moh_OtherSubsidiaryMember_F6D15109DA5A3F2974AFA0412D8C2EFA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OwnershipDomain_0F71C773B7C6932FF5BCA0412D8C8C1A" xlink:to="loc_moh_OtherSubsidiaryMember_F6D15109DA5A3F2974AFA0412D8C2EFA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_94CB5D0C4A235E9F698DA0412D8C28AF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_2ABD85DB7BF801DFE3A2A0412D8C9D2B" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_94CB5D0C4A235E9F698DA0412D8C28AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_0D7F4E476DA041330B64A0412D8CFEF4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_2ABD85DB7BF801DFE3A2A0412D8C9D2B" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_0D7F4E476DA041330B64A0412D8CFEF4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ImpairmentLossesGoodwillBalancesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillLineItems" xlink:label="loc_us-gaap_GoodwillLineItems_2F3AFBD005F7F7299B9895E3B414C379" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_D06C6614BB341E2F226B95E3B412D829" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_2F3AFBD005F7F7299B9895E3B414C379" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_D06C6614BB341E2F226B95E3B412D829" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_73BBB75A4C2F0FDD39E395E3B4133D73" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_D06C6614BB341E2F226B95E3B412D829" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_73BBB75A4C2F0FDD39E395E3B4133D73" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_150FE027F2FF2C6AEF8095E3B413FFEC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_73BBB75A4C2F0FDD39E395E3B4133D73" xlink:to="loc_us-gaap_SegmentDomain_150FE027F2FF2C6AEF8095E3B413FFEC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_150FE027F2FF2C6AEF8095E3B413FFEC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_73BBB75A4C2F0FDD39E395E3B4133D73" xlink:to="loc_us-gaap_SegmentDomain_150FE027F2FF2C6AEF8095E3B413FFEC" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_HealthPlansMember" xlink:label="loc_moh_HealthPlansMember_8CF4B525DC864CB3266C95E3B4132CAA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_150FE027F2FF2C6AEF8095E3B413FFEC" xlink:to="loc_moh_HealthPlansMember_8CF4B525DC864CB3266C95E3B4132CAA" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MedicaidSolutionsSegmentMember" xlink:label="loc_moh_MedicaidSolutionsSegmentMember_CE175683B757CF42CF8995E3B41361BE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_150FE027F2FF2C6AEF8095E3B413FFEC" xlink:to="loc_moh_MedicaidSolutionsSegmentMember_CE175683B757CF42CF8995E3B41361BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllOtherSegmentsMember" xlink:label="loc_us-gaap_AllOtherSegmentsMember_C77A3715A02148F78EBC95E3B4134BAB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_150FE027F2FF2C6AEF8095E3B413FFEC" xlink:to="loc_us-gaap_AllOtherSegmentsMember_C77A3715A02148F78EBC95E3B4134BAB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillGross" xlink:label="loc_us-gaap_GoodwillGross_C10116111F4C3EF780B495E3B414C040" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_2F3AFBD005F7F7299B9895E3B414C379" xlink:to="loc_us-gaap_GoodwillGross_C10116111F4C3EF780B495E3B414C040" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillImpairedAccumulatedImpairmentLoss" xlink:label="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_E6019A168289546198CA95E3B416B5C1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_2F3AFBD005F7F7299B9895E3B414C379" xlink:to="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_E6019A168289546198CA95E3B416B5C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_DAE55796F46A5BC557F095E3B41653D9" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_2F3AFBD005F7F7299B9895E3B414C379" xlink:to="loc_us-gaap_Goodwill_DAE55796F46A5BC557F095E3B41653D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillRollForward" xlink:label="loc_us-gaap_GoodwillRollForward_CE15639A9FBF3DA4E56A95E3B41799F3" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_2F3AFBD005F7F7299B9895E3B414C379" xlink:to="loc_us-gaap_GoodwillRollForward_CE15639A9FBF3DA4E56A95E3B41799F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_7D7A302527251C6B374195E3B4175B9E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_CE15639A9FBF3DA4E56A95E3B41799F3" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_7D7A302527251C6B374195E3B4175B9E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/ImpairmentLossesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/Investments" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/InvestmentsAvailableForSaleInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_02F2BDF0F9B29AEDFF408137D8E23B09" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_DF1FBF41507CE5711D208137D8E2A2B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_02F2BDF0F9B29AEDFF408137D8E23B09" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_DF1FBF41507CE5711D208137D8E2A2B5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_00037698FC7700248BF58137D8E2E489" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_DF1FBF41507CE5711D208137D8E2A2B5" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_00037698FC7700248BF58137D8E2E489" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_3D84F5E7767F2292D2738137D8E2F563_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_00037698FC7700248BF58137D8E2E489" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_3D84F5E7767F2292D2738137D8E2F563_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_3D84F5E7767F2292D2738137D8E2F563" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_00037698FC7700248BF58137D8E2E489" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_3D84F5E7767F2292D2738137D8E2F563" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_B62FEA9A0E8F269C96EB8137D8E20AFC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_3D84F5E7767F2292D2738137D8E2F563" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_B62FEA9A0E8F269C96EB8137D8E20AFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_2075CB42CB6F8F2CE0F68137D8E25A7A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_3D84F5E7767F2292D2738137D8E2F563" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_2075CB42CB6F8F2CE0F68137D8E25A7A" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MunicipalSecuritiesMember" xlink:label="loc_moh_MunicipalSecuritiesMember_49573A3E611D9304F75C8137D8E2EFB3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_3D84F5E7767F2292D2738137D8E2F563" xlink:to="loc_moh_MunicipalSecuritiesMember_49573A3E611D9304F75C8137D8E2EFB3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_CED702026CA6A33E6DA38137D8E28BBA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_02F2BDF0F9B29AEDFF408137D8E23B09" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_CED702026CA6A33E6DA38137D8E28BBA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_AA4300285FBDCD7EA8C48137D8E2D9B5" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_02F2BDF0F9B29AEDFF408137D8E23B09" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_AA4300285FBDCD7EA8C48137D8E2D9B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsLessThanOneYear" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsLessThanOneYear_41E810FF3290377528AE8137D8E266F1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_02F2BDF0F9B29AEDFF408137D8E23B09" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsLessThanOneYear_41E810FF3290377528AE8137D8E266F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_5BCA16CA14A014F0D7C88137D8E32A1D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_02F2BDF0F9B29AEDFF408137D8E23B09" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_5BCA16CA14A014F0D7C88137D8E32A1D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_1883E0A02B0EF699EBDC8137D8E383A0" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_02F2BDF0F9B29AEDFF408137D8E23B09" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_1883E0A02B0EF699EBDC8137D8E383A0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear_6503300DA4AF7E1B33BB8137D8E30124" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_02F2BDF0F9B29AEDFF408137D8E23B09" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsGreaterThanOrEqualToOneYear_6503300DA4AF7E1B33BB8137D8E30124" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/InvestmentsContractualMaturitiesOfInvestmentsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/InvestmentsHeldToMaturityInvestmentsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/InvestmentsSummaryOfInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5F3B07D1B5B66A4554028137D8EFEA6E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_B246A5179B860720E2318137D8EEF8FF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5F3B07D1B5B66A4554028137D8EFEA6E" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_B246A5179B860720E2318137D8EEF8FF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_AC250AE6D7FBF497916E8137D8EE8B91" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_B246A5179B860720E2318137D8EEF8FF" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_AC250AE6D7FBF497916E8137D8EE8B91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_AC250AE6D7FBF497916E8137D8EE8B91" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_AC250AE6D7FBF497916E8137D8EE8B91" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_ECE2899FC82F0628A7D48137D8EE41C5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_ECE2899FC82F0628A7D48137D8EE41C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_USTreasuryNotesSecuritiesMember" xlink:label="loc_us-gaap_USTreasuryNotesSecuritiesMember_B843FCE134693D32886B8137D8EEA49B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62" xlink:to="loc_us-gaap_USTreasuryNotesSecuritiesMember_B843FCE134693D32886B8137D8EEA49B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_3849665218374300DE938137D8EE0315" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_3849665218374300DE938137D8EE0315" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MunicipalSecuritiesMember" xlink:label="loc_moh_MunicipalSecuritiesMember_8B3E97DB1829561AF5478137D8EE703F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62" xlink:to="loc_moh_MunicipalSecuritiesMember_8B3E97DB1829561AF5478137D8EE703F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetBackedSecuritiesMember" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_D121609BF1D50D9E377D8137D8EE96F8" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_D121609BF1D50D9E377D8137D8EE96F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CertificatesOfDepositMember" xlink:label="loc_us-gaap_CertificatesOfDepositMember_7421319CF81976251E908137D8EE5808" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62" xlink:to="loc_us-gaap_CertificatesOfDepositMember_7421319CF81976251E908137D8EE5808" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CurrentInvestmentsMember" xlink:label="loc_moh_CurrentInvestmentsMember_9AE00D3A714C28F957C78137D8EECB1D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_260627227419BEABCE448137D8EEBB62" xlink:to="loc_moh_CurrentInvestmentsMember_9AE00D3A714C28F957C78137D8EECB1D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_8EBF85DB31FCFCF2DC838137D8EED5E7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_B246A5179B860720E2318137D8EEF8FF" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_8EBF85DB31FCFCF2DC838137D8EED5E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_1A2A24CB067972461BF88137D8EE85AF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_8EBF85DB31FCFCF2DC838137D8EED5E7" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_1A2A24CB067972461BF88137D8EE85AF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_1A2A24CB067972461BF88137D8EE85AF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_8EBF85DB31FCFCF2DC838137D8EED5E7" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_1A2A24CB067972461BF88137D8EE85AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_3106B3F02A9DFF688D108137D8EE9ED1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_1A2A24CB067972461BF88137D8EE85AF" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_3106B3F02A9DFF688D108137D8EE9ED1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_8A144AA01E6C2934CE628137D8EFC844" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_1A2A24CB067972461BF88137D8EE85AF" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_8A144AA01E6C2934CE628137D8EFC844" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_RestrictedInvestmentsCurrentMember" xlink:label="loc_moh_RestrictedInvestmentsCurrentMember_F53573AA2FFD81FC74B78137D8EF76B8" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_1A2A24CB067972461BF88137D8EE85AF" xlink:to="loc_moh_RestrictedInvestmentsCurrentMember_F53573AA2FFD81FC74B78137D8EF76B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_BCE8A36D4AC72B95B0618137D8EF6FD2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5F3B07D1B5B66A4554028137D8EFEA6E" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_BCE8A36D4AC72B95B0618137D8EF6FD2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_BE7A158CF6B33E29B9F28137D8EF9057" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5F3B07D1B5B66A4554028137D8EFEA6E" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_BE7A158CF6B33E29B9F28137D8EF9057" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_4197FBB2A244F5D242528137D8EFCF3E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5F3B07D1B5B66A4554028137D8EFEA6E" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_4197FBB2A244F5D242528137D8EFCF3E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecurities_FDD98773872B2A4A08048137D8EF8E26" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5F3B07D1B5B66A4554028137D8EFEA6E" xlink:to="loc_us-gaap_AvailableForSaleSecurities_FDD98773872B2A4A08048137D8EF8E26" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/InvestmentsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayable" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayableAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_364BABBB88C43DDF5D4BA064925BF13A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_B972F535B403C4989A69A064925B59D6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_364BABBB88C43DDF5D4BA064925BF13A" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_B972F535B403C4989A69A064925B59D6" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_D452B95845AE8BFAB4F3A064925B5032" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_B972F535B403C4989A69A064925B59D6" xlink:to="loc_us-gaap_RangeAxis_D452B95845AE8BFAB4F3A064925B5032" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_06EDE8E1F24AB6D60A08A064925BAF34_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_D452B95845AE8BFAB4F3A064925B5032" xlink:to="loc_us-gaap_RangeMember_06EDE8E1F24AB6D60A08A064925BAF34_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_06EDE8E1F24AB6D60A08A064925BAF34" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_D452B95845AE8BFAB4F3A064925B5032" xlink:to="loc_us-gaap_RangeMember_06EDE8E1F24AB6D60A08A064925BAF34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_68E401113AD312833135A064925BFE4E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_06EDE8E1F24AB6D60A08A064925BAF34" xlink:to="loc_us-gaap_MinimumMember_68E401113AD312833135A064925BFE4E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_CDF54FFBA307282C882BA064925BFDA7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_06EDE8E1F24AB6D60A08A064925BAF34" xlink:to="loc_us-gaap_MaximumMember_CDF54FFBA307282C882BA064925BFDA7" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ShortDurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseUncollectibleClaimsAssumption" xlink:label="loc_moh_ShortDurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseUncollectibleClaimsAssumption_6605648D174FD37318C1A0717424D8E8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_364BABBB88C43DDF5D4BA064925BF13A" xlink:to="loc_moh_ShortDurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseUncollectibleClaimsAssumption_6605648D174FD37318C1A0717424D8E8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense_BB2B77B29DE1D6BD3891A064925B994C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_364BABBB88C43DDF5D4BA064925BF13A" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense_BB2B77B29DE1D6BD3891A064925B994C" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayableComponentsOfChangeInMedicalClaimsAndBenefitsPayableDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayableMedicalClaimsAndFutureBenefitsDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/MedicalClaimsAndBenefitsPayableTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/NetLossIncomePerShare" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/NetLossIncomePerShareDetail" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/NetLossIncomePerShareTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/RelatedPartyTransactions" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/RelatedPartyTransactionsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_516EDBA99724C2BCF4888137D7D024AD" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_EBDF76F93AF507FC3A2E8137D7CF90D8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_516EDBA99724C2BCF4888137D7D024AD" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_EBDF76F93AF507FC3A2E8137D7CF90D8" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_003F39E3144EDBB8A0C88137D7CFC340" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_EBDF76F93AF507FC3A2E8137D7CF90D8" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_003F39E3144EDBB8A0C88137D7CFC340" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_B2EB44097786EBAB27898137D7CF1378_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_003F39E3144EDBB8A0C88137D7CFC340" xlink:to="loc_us-gaap_RelatedPartyDomain_B2EB44097786EBAB27898137D7CF1378_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain_B2EB44097786EBAB27898137D7CF1378" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_003F39E3144EDBB8A0C88137D7CFC340" xlink:to="loc_us-gaap_RelatedPartyDomain_B2EB44097786EBAB27898137D7CF1378" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="loc_us-gaap_AffiliatedEntityMember_A4847936446A031958E08137D7D0CD82" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_B2EB44097786EBAB27898137D7CF1378" xlink:to="loc_us-gaap_AffiliatedEntityMember_A4847936446A031958E08137D7D0CD82" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_1D464681C4AA7516ACD58137D7D09D69" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_516EDBA99724C2BCF4888137D7D024AD" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_1D464681C4AA7516ACD58137D7D09D69" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/RestructuringAndSeparationCosts" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/RestructuringAndSeparationCostsExpectedCostsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_C47DD248D71DEEDF7AC7A0412D759AA1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_CCFD794A93DB56CC6323A0412D74C944" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_C47DD248D71DEEDF7AC7A0412D759AA1" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_CCFD794A93DB56CC6323A0412D74C944" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_A176EB89C7F769E4C766A0412D74E04E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_CCFD794A93DB56CC6323A0412D74C944" xlink:to="loc_us-gaap_StatementScenarioAxis_A176EB89C7F769E4C766A0412D74E04E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_76183687DDF526EDEBD0A0412D749379_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_A176EB89C7F769E4C766A0412D74E04E" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_76183687DDF526EDEBD0A0412D749379_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_76183687DDF526EDEBD0A0412D749379" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_A176EB89C7F769E4C766A0412D74E04E" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_76183687DDF526EDEBD0A0412D749379" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioForecastMember" xlink:label="loc_us-gaap_ScenarioForecastMember_BEE76E08F5289C74E20AA0412D7405CB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_76183687DDF526EDEBD0A0412D749379" xlink:to="loc_us-gaap_ScenarioForecastMember_BEE76E08F5289C74E20AA0412D7405CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_349FB96184C22E3877DBA0412D745B5E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_CCFD794A93DB56CC6323A0412D74C944" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_349FB96184C22E3877DBA0412D745B5E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_DB1E13F2F02CCF9B14F3A0412D744550_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_349FB96184C22E3877DBA0412D745B5E" xlink:to="loc_us-gaap_SegmentDomain_DB1E13F2F02CCF9B14F3A0412D744550_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_DB1E13F2F02CCF9B14F3A0412D744550" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_349FB96184C22E3877DBA0412D745B5E" xlink:to="loc_us-gaap_SegmentDomain_DB1E13F2F02CCF9B14F3A0412D744550" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_HealthPlansMember" xlink:label="loc_moh_HealthPlansMember_63242F8DE06B1B23A0ECA0412D745268" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_DB1E13F2F02CCF9B14F3A0412D744550" xlink:to="loc_moh_HealthPlansMember_63242F8DE06B1B23A0ECA0412D745268" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllOtherSegmentsMember" xlink:label="loc_us-gaap_AllOtherSegmentsMember_F288580B109A92D43D66A0412D74DDFE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_DB1E13F2F02CCF9B14F3A0412D744550" xlink:to="loc_us-gaap_AllOtherSegmentsMember_F288580B109A92D43D66A0412D74DDFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_BDC59AB1A5FEF031F5C5A0412D74FDB7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_CCFD794A93DB56CC6323A0412D74C944" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_BDC59AB1A5FEF031F5C5A0412D74FDB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_E46843D30BDDE3F555E9A0412D740F6D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_BDC59AB1A5FEF031F5C5A0412D74FDB7" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_E46843D30BDDE3F555E9A0412D740F6D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_E46843D30BDDE3F555E9A0412D740F6D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_BDC59AB1A5FEF031F5C5A0412D74FDB7" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_E46843D30BDDE3F555E9A0412D740F6D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeSeveranceMember" xlink:label="loc_us-gaap_EmployeeSeveranceMember_F385D4AABD203E335ACCA0412D745459" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_E46843D30BDDE3F555E9A0412D740F6D" xlink:to="loc_us-gaap_EmployeeSeveranceMember_F385D4AABD203E335ACCA0412D745459" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherRestructuringMember" xlink:label="loc_us-gaap_OtherRestructuringMember_61136393F112BE218A81A0412D746C13" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_E46843D30BDDE3F555E9A0412D740F6D" xlink:to="loc_us-gaap_OtherRestructuringMember_61136393F112BE218A81A0412D746C13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_C273FED1A57EE59B4020A0412D75489E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_CCFD794A93DB56CC6323A0412D74C944" xlink:to="loc_us-gaap_RangeAxis_C273FED1A57EE59B4020A0412D75489E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_5416111D0EE7D63CB3B4A0412D759735_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_C273FED1A57EE59B4020A0412D75489E" xlink:to="loc_us-gaap_RangeMember_5416111D0EE7D63CB3B4A0412D759735_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_5416111D0EE7D63CB3B4A0412D759735" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_C273FED1A57EE59B4020A0412D75489E" xlink:to="loc_us-gaap_RangeMember_5416111D0EE7D63CB3B4A0412D759735" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_644AD5517DF5BB17A6CFA0412D7524CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_5416111D0EE7D63CB3B4A0412D759735" xlink:to="loc_us-gaap_MinimumMember_644AD5517DF5BB17A6CFA0412D7524CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_29C16EDB812FB54598A5A0412D75CDD4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_5416111D0EE7D63CB3B4A0412D759735" xlink:to="loc_us-gaap_MaximumMember_29C16EDB812FB54598A5A0412D75CDD4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCosts" xlink:label="loc_us-gaap_RestructuringCosts_6E4F94F7265778A23346A0412D75019C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_C47DD248D71DEEDF7AC7A0412D759AA1" xlink:to="loc_us-gaap_RestructuringCosts_6E4F94F7265778A23346A0412D75019C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostsAndAssetImpairmentChargesAbstract" xlink:label="loc_us-gaap_RestructuringCostsAndAssetImpairmentChargesAbstract_DEA1ECF76F087AA7A706A0412D753048" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_C47DD248D71DEEDF7AC7A0412D759AA1" xlink:to="loc_us-gaap_RestructuringCostsAndAssetImpairmentChargesAbstract_DEA1ECF76F087AA7A706A0412D753048" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringAndRelatedCostExpectedCost1" xlink:label="loc_us-gaap_RestructuringAndRelatedCostExpectedCost1_91E95CABB6167359ED98A0412D7529EE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostsAndAssetImpairmentChargesAbstract_DEA1ECF76F087AA7A706A0412D753048" xlink:to="loc_us-gaap_RestructuringAndRelatedCostExpectedCost1_91E95CABB6167359ED98A0412D7529EE" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/RestructuringAndSeparationCostsOtherRestructuringCostsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_47F6B0D9A1BCE830752E852F12EF089E" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_3FCCDB8117B13D0F7DC0852F12EEEEFB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_47F6B0D9A1BCE830752E852F12EF089E" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_3FCCDB8117B13D0F7DC0852F12EEEEFB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_A9E8C9C534EA9B916C22852F12EE3722" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_3FCCDB8117B13D0F7DC0852F12EEEEFB" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_A9E8C9C534EA9B916C22852F12EE3722" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_1957695243F81F8EC6EE852F12EE7143_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_A9E8C9C534EA9B916C22852F12EE3722" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_1957695243F81F8EC6EE852F12EE7143_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_1957695243F81F8EC6EE852F12EE7143" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_A9E8C9C534EA9B916C22852F12EE3722" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_1957695243F81F8EC6EE852F12EE7143" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeSeveranceMember" xlink:label="loc_us-gaap_EmployeeSeveranceMember_5F295869A0B8CC9594A9852F12EF298C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_1957695243F81F8EC6EE852F12EE7143" xlink:to="loc_us-gaap_EmployeeSeveranceMember_5F295869A0B8CC9594A9852F12EF298C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherRestructuringMember" xlink:label="loc_us-gaap_OtherRestructuringMember_2C0FA85B42EB20A562AE852F12EF2C27" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_1957695243F81F8EC6EE852F12EE7143" xlink:to="loc_us-gaap_OtherRestructuringMember_2C0FA85B42EB20A562AE852F12EF2C27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserveRollForward" xlink:label="loc_us-gaap_RestructuringReserveRollForward_DB25B0F1A88EAC9D4669852F12EF96B0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_47F6B0D9A1BCE830752E852F12EF089E" xlink:to="loc_us-gaap_RestructuringReserveRollForward_DB25B0F1A88EAC9D4669852F12EF96B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserve" xlink:label="loc_us-gaap_RestructuringReserve_09B8C1135E4DE44A67EF852F12EFF7C0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_DB25B0F1A88EAC9D4669852F12EF96B0" xlink:to="loc_us-gaap_RestructuringReserve_09B8C1135E4DE44A67EF852F12EFF7C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_22DBB7390A99C57C6A46852F12EF72CF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_DB25B0F1A88EAC9D4669852F12EF96B0" xlink:to="loc_us-gaap_RestructuringCharges_22DBB7390A99C57C6A46852F12EF72CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForRestructuring" xlink:label="loc_us-gaap_PaymentsForRestructuring_29E9C03FEC77A8377EA9852F12EF1B49" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_DB25B0F1A88EAC9D4669852F12EF96B0" xlink:to="loc_us-gaap_PaymentsForRestructuring_29E9C03FEC77A8377EA9852F12EF1B49" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserveSettledWithoutCash2" xlink:label="loc_us-gaap_RestructuringReserveSettledWithoutCash2_105B64138F5C51EA4DE88536503FEAC8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_DB25B0F1A88EAC9D4669852F12EF96B0" xlink:to="loc_us-gaap_RestructuringReserveSettledWithoutCash2_105B64138F5C51EA4DE88536503FEAC8" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/RestructuringAndSeparationCostsSeparationCostsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveLineItems" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_012B7B914E1E85CC5FA79A494CE58D88" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_559AD25DCF8358FF86B79A494CDF2512" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_012B7B914E1E85CC5FA79A494CE58D88" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_559AD25DCF8358FF86B79A494CDF2512" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis_BA837985CAC6EABF77A39A494CDF9119" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_559AD25DCF8358FF86B79A494CDF2512" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis_BA837985CAC6EABF77A39A494CDF9119" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredBonusAndProfitSharingArrangementIndividualContractTypeOfDeferredCompensationDomain" xlink:label="loc_us-gaap_DeferredBonusAndProfitSharingArrangementIndividualContractTypeOfDeferredCompensationDomain_ECC26FB05658DAF095469A494CDFF644_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis_BA837985CAC6EABF77A39A494CDF9119" xlink:to="loc_us-gaap_DeferredBonusAndProfitSharingArrangementIndividualContractTypeOfDeferredCompensationDomain_ECC26FB05658DAF095469A494CDFF644_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredBonusAndProfitSharingArrangementIndividualContractTypeOfDeferredCompensationDomain" xlink:label="loc_us-gaap_DeferredBonusAndProfitSharingArrangementIndividualContractTypeOfDeferredCompensationDomain_ECC26FB05658DAF095469A494CDFF644" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualExcludingShareBasedPaymentsAndPostretirementBenefitsByTypeOfDeferredCompensationAxis_BA837985CAC6EABF77A39A494CDF9119" xlink:to="loc_us-gaap_DeferredBonusAndProfitSharingArrangementIndividualContractTypeOfDeferredCompensationDomain_ECC26FB05658DAF095469A494CDFF644" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_DeferredTerminationFeeMember" xlink:label="loc_moh_DeferredTerminationFeeMember_BAD0F2AC7155BF829D0F9A494CDFAD29" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredBonusAndProfitSharingArrangementIndividualContractTypeOfDeferredCompensationDomain_ECC26FB05658DAF095469A494CDFF644" xlink:to="loc_moh_DeferredTerminationFeeMember_BAD0F2AC7155BF829D0F9A494CDFAD29" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredBonusMember" xlink:label="loc_us-gaap_DeferredBonusMember_A1BAE9A6A1B4F6E272009A494CDF42BE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredBonusAndProfitSharingArrangementIndividualContractTypeOfDeferredCompensationDomain_ECC26FB05658DAF095469A494CDFF644" xlink:to="loc_us-gaap_DeferredBonusMember_A1BAE9A6A1B4F6E272009A494CDF42BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TitleOfIndividualAxis" xlink:label="loc_us-gaap_TitleOfIndividualAxis_272479ACBADF3929C5C59A494CDF722C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_559AD25DCF8358FF86B79A494CDF2512" xlink:to="loc_us-gaap_TitleOfIndividualAxis_272479ACBADF3929C5C59A494CDF722C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_9C32FFDEFF281E32F7569A494CDF9D5D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TitleOfIndividualAxis_272479ACBADF3929C5C59A494CDF722C" xlink:to="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_9C32FFDEFF281E32F7569A494CDF9D5D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_9C32FFDEFF281E32F7569A494CDF9D5D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TitleOfIndividualAxis_272479ACBADF3929C5C59A494CDF722C" xlink:to="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_9C32FFDEFF281E32F7569A494CDF9D5D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ExecutiveOfficerMember" xlink:label="loc_us-gaap_ExecutiveOfficerMember_6739C7D5D297E14C8E749A494CDF168B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_9C32FFDEFF281E32F7569A494CDF9D5D" xlink:to="loc_us-gaap_ExecutiveOfficerMember_6739C7D5D297E14C8E749A494CDF168B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ChiefExecutiveOfficerMember" xlink:label="loc_us-gaap_ChiefExecutiveOfficerMember_65A6C55ADB75197235319A494CE0DBD0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_9C32FFDEFF281E32F7569A494CDF9D5D" xlink:to="loc_us-gaap_ChiefExecutiveOfficerMember_65A6C55ADB75197235319A494CE0DBD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ChiefFinancialOfficerMember" xlink:label="loc_us-gaap_ChiefFinancialOfficerMember_7C2B034643AF7E9797199A494CE531F4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_9C32FFDEFF281E32F7569A494CDF9D5D" xlink:to="loc_us-gaap_ChiefFinancialOfficerMember_7C2B034643AF7E9797199A494CE531F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCostAndReserveAxis" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_EF9C31DF780A2CED02CA9A494CE58E29" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_559AD25DCF8358FF86B79A494CDF2512" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_EF9C31DF780A2CED02CA9A494CE58E29" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_AD10941DA002FED06F439A494CE57B1B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_EF9C31DF780A2CED02CA9A494CE58E29" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_AD10941DA002FED06F439A494CE57B1B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfRestructuringDomain" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_AD10941DA002FED06F439A494CE57B1B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_EF9C31DF780A2CED02CA9A494CE58E29" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_AD10941DA002FED06F439A494CE57B1B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeSeveranceMember" xlink:label="loc_us-gaap_EmployeeSeveranceMember_E967E83AC8A24F63571A9A494CE5F3F8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_AD10941DA002FED06F439A494CE57B1B" xlink:to="loc_us-gaap_EmployeeSeveranceMember_E967E83AC8A24F63571A9A494CE5F3F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_B520245E6A01A99ABD9D9AAD5D628B69" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_559AD25DCF8358FF86B79A494CDF2512" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_B520245E6A01A99ABD9D9AAD5D628B69" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_56C53237EB24FDB9F2CB9AADBA231675_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_B520245E6A01A99ABD9D9AAD5D628B69" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_56C53237EB24FDB9F2CB9AADBA231675_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_56C53237EB24FDB9F2CB9AADBA231675" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_B520245E6A01A99ABD9D9AAD5D628B69" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_56C53237EB24FDB9F2CB9AADBA231675" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LaborForceConcentrationRiskMember" xlink:label="loc_us-gaap_LaborForceConcentrationRiskMember_05443A720D37F7C3D7A69AB3D6E6A861" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_56C53237EB24FDB9F2CB9AADBA231675" xlink:to="loc_us-gaap_LaborForceConcentrationRiskMember_05443A720D37F7C3D7A69AB3D6E6A861" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_3A2505C8B4EEE13B9EF29AAD3351EE32" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_559AD25DCF8358FF86B79A494CDF2512" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_3A2505C8B4EEE13B9EF29AAD3351EE32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D0E201591C6CAF537B199AB02AF21F2E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_3A2505C8B4EEE13B9EF29AAD3351EE32" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D0E201591C6CAF537B199AB02AF21F2E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D0E201591C6CAF537B199AB02AF21F2E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_3A2505C8B4EEE13B9EF29AAD3351EE32" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D0E201591C6CAF537B199AB02AF21F2E" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_NumberOfPositionsEliminatedCorporateNonSegmentAndHealthPlansSegmentMemberMember" xlink:label="loc_moh_NumberOfPositionsEliminatedCorporateNonSegmentAndHealthPlansSegmentMemberMember_9A6ED85D4051B9BE97819AB300042EDF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D0E201591C6CAF537B199AB02AF21F2E" xlink:to="loc_moh_NumberOfPositionsEliminatedCorporateNonSegmentAndHealthPlansSegmentMemberMember_9A6ED85D4051B9BE97819AB300042EDF" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_NumberOfPositionsEliminatedHealthPlansSegmentMemberMember" xlink:label="loc_moh_NumberOfPositionsEliminatedHealthPlansSegmentMemberMember_EC2F525FBD2475D01FF99AB37CADF7AA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D0E201591C6CAF537B199AB02AF21F2E" xlink:to="loc_moh_NumberOfPositionsEliminatedHealthPlansSegmentMemberMember_EC2F525FBD2475D01FF99AB37CADF7AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualCashAwardsGrantedPercentage" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualCashAwardsGrantedPercentage_D6D56016C47393370F059A494CE5C930" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_012B7B914E1E85CC5FA79A494CE58D88" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualCashAwardsGrantedPercentage_D6D56016C47393370F059A494CE5C930" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCharges" xlink:label="loc_us-gaap_RestructuringCharges_A5BC5BCFF44F62C65AEE9A494CE50A27" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_012B7B914E1E85CC5FA79A494CE58D88" xlink:to="loc_us-gaap_RestructuringCharges_A5BC5BCFF44F62C65AEE9A494CE50A27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringReserveSettledWithoutCash2" xlink:label="loc_us-gaap_RestructuringReserveSettledWithoutCash2_6979A22B9A98D849E5279A494CE5A035" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_012B7B914E1E85CC5FA79A494CE58D88" xlink:to="loc_us-gaap_RestructuringReserveSettledWithoutCash2_6979A22B9A98D849E5279A494CE5A035" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_7A4E590C9B7B6492AD4C9AAB7A1FD231" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_012B7B914E1E85CC5FA79A494CE58D88" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_7A4E590C9B7B6492AD4C9AAB7A1FD231" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminated" xlink:label="loc_us-gaap_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminated_D6D434268AC2319397999A494CE577D9" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_012B7B914E1E85CC5FA79A494CE58D88" xlink:to="loc_us-gaap_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminated_D6D434268AC2319397999A494CE577D9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/RestructuringAndSeparationCostsTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SegmentInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SegmentInformationAdditionalInformationDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SegmentInformationReconciliationOfGrossMarginToConsolidatedIncomeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_13DC673B9D23889C6749852F12D0C410" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_35F2DAA8741FB3CDD215852F12CF5CE9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_13DC673B9D23889C6749852F12D0C410" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_35F2DAA8741FB3CDD215852F12CF5CE9" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_4C976B343815C489F7D8852F12CFDDD0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_35F2DAA8741FB3CDD215852F12CF5CE9" xlink:to="loc_us-gaap_ConsolidationItemsAxis_4C976B343815C489F7D8852F12CFDDD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_DB1C47CB410841CAF293852F12CFE251_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_4C976B343815C489F7D8852F12CFDDD0" xlink:to="loc_us-gaap_ConsolidationItemsDomain_DB1C47CB410841CAF293852F12CFE251_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_DB1C47CB410841CAF293852F12CFE251" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_4C976B343815C489F7D8852F12CFDDD0" xlink:to="loc_us-gaap_ConsolidationItemsDomain_DB1C47CB410841CAF293852F12CFE251" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="loc_us-gaap_OperatingSegmentsMember_F447E5AB32BADF1865EC852F12CF5A90" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_DB1C47CB410841CAF293852F12CFE251" xlink:to="loc_us-gaap_OperatingSegmentsMember_F447E5AB32BADF1865EC852F12CF5A90" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaterialReconcilingItemsMember" xlink:label="loc_us-gaap_MaterialReconcilingItemsMember_CC11770F049AB1C9ABA3852F12CF1096" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_DB1C47CB410841CAF293852F12CFE251" xlink:to="loc_us-gaap_MaterialReconcilingItemsMember_CC11770F049AB1C9ABA3852F12CF1096" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_2E014489FB6ED58D9931852F12CF4629" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_35F2DAA8741FB3CDD215852F12CF5CE9" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_2E014489FB6ED58D9931852F12CF4629" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_955CBD06F77C24DD958D852F12CF74E4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2E014489FB6ED58D9931852F12CF4629" xlink:to="loc_us-gaap_SegmentDomain_955CBD06F77C24DD958D852F12CF74E4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_955CBD06F77C24DD958D852F12CF74E4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2E014489FB6ED58D9931852F12CF4629" xlink:to="loc_us-gaap_SegmentDomain_955CBD06F77C24DD958D852F12CF74E4" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_HealthPlansMember" xlink:label="loc_moh_HealthPlansMember_128EF5BDFF142DC5B223852F12CF7276" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_955CBD06F77C24DD958D852F12CF74E4" xlink:to="loc_moh_HealthPlansMember_128EF5BDFF142DC5B223852F12CF7276" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MedicaidSolutionsSegmentMember" xlink:label="loc_moh_MedicaidSolutionsSegmentMember_C672752F78E7298A8EE8852F12D0F8B6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_955CBD06F77C24DD958D852F12CF74E4" xlink:to="loc_moh_MedicaidSolutionsSegmentMember_C672752F78E7298A8EE8852F12D0F8B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllOtherSegmentsMember" xlink:label="loc_us-gaap_AllOtherSegmentsMember_56F56FF5783AC6C4785E852F12D0C164" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_955CBD06F77C24DD958D852F12CF74E4" xlink:to="loc_us-gaap_AllOtherSegmentsMember_56F56FF5783AC6C4785E852F12D0C164" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_EB1DC31A8D5A20FCC05E852F12D0C155" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_13DC673B9D23889C6749852F12D0C410" xlink:to="loc_us-gaap_GrossProfit_EB1DC31A8D5A20FCC05E852F12D0C155" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_5AC5CC3F9F79601D7E6E852F12D053D2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_13DC673B9D23889C6749852F12D0C410" xlink:to="loc_us-gaap_Revenues_5AC5CC3F9F79601D7E6E852F12D053D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="loc_us-gaap_CostsAndExpenses_CE42706D28166D436AC5852F12D09F21" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_13DC673B9D23889C6749852F12D0C410" xlink:to="loc_us-gaap_CostsAndExpenses_CE42706D28166D436AC5852F12D09F21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_EBB45F81F9CC6B50BEEC852F12D0AE1A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_13DC673B9D23889C6749852F12D0C410" xlink:to="loc_us-gaap_OperatingIncomeLoss_EBB45F81F9CC6B50BEEC852F12D0AE1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_A3FCC99AB65301F41B8E852F12D0E636" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_13DC673B9D23889C6749852F12D0C410" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_A3FCC99AB65301F41B8E852F12D0E636" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_BC6DA6B2203D4B25A002852F12D1C3B7" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_13DC673B9D23889C6749852F12D0C410" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_BC6DA6B2203D4B25A002852F12D1C3B7" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SegmentInformationScheduleOfOperatingSegmentInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_C45C710576FE4F49F86595E61A1635DE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D37BB9D2451BB2CEC6E795E61A15D55C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_C45C710576FE4F49F86595E61A1635DE" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D37BB9D2451BB2CEC6E795E61A15D55C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_2FDCED18BF331DF1BD3695E61A157D71" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_D37BB9D2451BB2CEC6E795E61A15D55C" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_2FDCED18BF331DF1BD3695E61A157D71" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_C952BC8486539203487695E61A150CDF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2FDCED18BF331DF1BD3695E61A157D71" xlink:to="loc_us-gaap_SegmentDomain_C952BC8486539203487695E61A150CDF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_C952BC8486539203487695E61A150CDF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2FDCED18BF331DF1BD3695E61A157D71" xlink:to="loc_us-gaap_SegmentDomain_C952BC8486539203487695E61A150CDF" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_HealthPlansMember" xlink:label="loc_moh_HealthPlansMember_62A1B3EF83E9AC51B31995E61A16F988" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C952BC8486539203487695E61A150CDF" xlink:to="loc_moh_HealthPlansMember_62A1B3EF83E9AC51B31995E61A16F988" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MedicaidSolutionsSegmentMember" xlink:label="loc_moh_MedicaidSolutionsSegmentMember_F2A8510C39A2C27467F295E61A16AF00" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C952BC8486539203487695E61A150CDF" xlink:to="loc_moh_MedicaidSolutionsSegmentMember_F2A8510C39A2C27467F295E61A16AF00" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllOtherSegmentsMember" xlink:label="loc_us-gaap_AllOtherSegmentsMember_AF65FA5C3B0686A9A79995E61A1601C1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_C952BC8486539203487695E61A150CDF" xlink:to="loc_us-gaap_AllOtherSegmentsMember_AF65FA5C3B0686A9A79995E61A1601C1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_D245CAE2FE573F9E23F695E61A16A53E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_C45C710576FE4F49F86595E61A1635DE" xlink:to="loc_us-gaap_Revenues_D245CAE2FE573F9E23F695E61A16A53E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_966E7F57E141B32738F995E61A16FE8F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_C45C710576FE4F49F86595E61A1635DE" xlink:to="loc_us-gaap_GrossProfit_966E7F57E141B32738F995E61A16FE8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetImpairment" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetImpairment_A96B6C8411399151976795E9EDFA7D0F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_C45C710576FE4F49F86595E61A1635DE" xlink:to="loc_us-gaap_GoodwillAndIntangibleAssetImpairment_A96B6C8411399151976795E9EDFA7D0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCosts" xlink:label="loc_us-gaap_RestructuringCosts_23F157BE0360FA9D454895E61A178878" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_C45C710576FE4F49F86595E61A1635DE" xlink:to="loc_us-gaap_RestructuringCosts_23F157BE0360FA9D454895E61A178878" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_E04D318417794A2F4BAF95E61A1754E4" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_C45C710576FE4F49F86595E61A1635DE" xlink:to="loc_us-gaap_Assets_E04D318417794A2F4BAF95E61A1754E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetIncludingGoodwill_F1A17E18D4D4CA2396F195E61A170D82" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_C45C710576FE4F49F86595E61A1635DE" xlink:to="loc_us-gaap_IntangibleAssetsNetIncludingGoodwill_F1A17E18D4D4CA2396F195E61A170D82" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SegmentInformationTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SignificantAccountingPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SignificantAccountingPolicies3RProgramReceivablesPayablesDetails" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SignificantAccountingPoliciesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:href="moh-20170630.xsd#moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems" xlink:label="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_32ADD2A3E259456DCE068137D92A1EFA" xlink:type="locator" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable" xlink:label="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_8676D9B6A6DCCA9EBEB98137D9287B06" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_32ADD2A3E259456DCE068137D92A1EFA" xlink:to="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_8676D9B6A6DCCA9EBEB98137D9287B06" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_0FA73F8B21C97EDFA0F58137D928EAB5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_8676D9B6A6DCCA9EBEB98137D9287B06" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_0FA73F8B21C97EDFA0F58137D928EAB5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_6BFF0A51D37096697E9E8137D928401D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_0FA73F8B21C97EDFA0F58137D928EAB5" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_6BFF0A51D37096697E9E8137D928401D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_6BFF0A51D37096697E9E8137D928401D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_0FA73F8B21C97EDFA0F58137D928EAB5" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_6BFF0A51D37096697E9E8137D928401D" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MedicalPremiumLiabilityDuetoAgencyMember" xlink:label="loc_moh_MedicalPremiumLiabilityDuetoAgencyMember_B3D822303696C22B25C08137D92906F9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_6BFF0A51D37096697E9E8137D928401D" xlink:to="loc_moh_MedicalPremiumLiabilityDuetoAgencyMember_B3D822303696C22B25C08137D92906F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:label="loc_us-gaap_ProductOrServiceAxis_0D24481760E4DFF6E8AF8137D929B257" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_8676D9B6A6DCCA9EBEB98137D9287B06" xlink:to="loc_us-gaap_ProductOrServiceAxis_0D24481760E4DFF6E8AF8137D929B257" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_50983FECB9275C212CE58137D929708E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ProductOrServiceAxis_0D24481760E4DFF6E8AF8137D929B257" xlink:to="loc_us-gaap_ProductsAndServicesDomain_50983FECB9275C212CE58137D929708E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:label="loc_us-gaap_ProductsAndServicesDomain_50983FECB9275C212CE58137D929708E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ProductOrServiceAxis_0D24481760E4DFF6E8AF8137D929B257" xlink:to="loc_us-gaap_ProductsAndServicesDomain_50983FECB9275C212CE58137D929708E" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MedicaidExpansionMember" xlink:label="loc_moh_MedicaidExpansionMember_C962CA81E8D6EA7DE4D98137D929A3CE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ProductsAndServicesDomain_50983FECB9275C212CE58137D929708E" xlink:to="loc_moh_MedicaidExpansionMember_C962CA81E8D6EA7DE4D98137D929A3CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_D8415E50A6114DE3A50F8137D929AF9E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_8676D9B6A6DCCA9EBEB98137D9287B06" xlink:to="loc_us-gaap_StatementScenarioAxis_D8415E50A6114DE3A50F8137D929AF9E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_32FDE233DCA6AC3FC5878137D92A64DC_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_D8415E50A6114DE3A50F8137D929AF9E" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_32FDE233DCA6AC3FC5878137D92A64DC_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_32FDE233DCA6AC3FC5878137D92A64DC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_D8415E50A6114DE3A50F8137D929AF9E" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_32FDE233DCA6AC3FC5878137D92A64DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestatementAdjustmentMember" xlink:label="loc_us-gaap_RestatementAdjustmentMember_E0331AE781521B2250438137D92A3547" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScenarioUnspecifiedDomain_32FDE233DCA6AC3FC5878137D92A64DC" xlink:to="loc_us-gaap_RestatementAdjustmentMember_E0331AE781521B2250438137D92A3547" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_9320CC3A44A9FBAD57318137D92A0780" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_8676D9B6A6DCCA9EBEB98137D9287B06" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_9320CC3A44A9FBAD57318137D92A0780" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_C507DFCD815233F8BB858137D92A2DCE_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_9320CC3A44A9FBAD57318137D92A0780" xlink:to="loc_us-gaap_TypeOfAdoptionMember_C507DFCD815233F8BB858137D92A2DCE_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="loc_us-gaap_TypeOfAdoptionMember_C507DFCD815233F8BB858137D92A2DCE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_9320CC3A44A9FBAD57318137D92A0780" xlink:to="loc_us-gaap_TypeOfAdoptionMember_C507DFCD815233F8BB858137D92A2DCE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountingStandardsUpdate201409Member" xlink:label="loc_us-gaap_AccountingStandardsUpdate201409Member_A49E8176F58E8C4664C18137D92AE073" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_C507DFCD815233F8BB858137D92A2DCE" xlink:to="loc_us-gaap_AccountingStandardsUpdate201409Member_A49E8176F58E8C4664C18137D92AE073" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MedicalPremiumsLiabilityMedicalCareCostsThreshold" xlink:label="loc_moh_MedicalPremiumsLiabilityMedicalCareCostsThreshold_E7FE2661007A3268962B8137D92AF379" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_32ADD2A3E259456DCE068137D92A1EFA" xlink:to="loc_moh_MedicalPremiumsLiabilityMedicalCareCostsThreshold_E7FE2661007A3268962B8137D92AF379" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MedicalPremiumLiabilityDueToAgency" xlink:label="loc_moh_MedicalPremiumLiabilityDueToAgency_6E60BECE539BDA59539A8137D92BAAF0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_32ADD2A3E259456DCE068137D92A1EFA" xlink:to="loc_moh_MedicalPremiumLiabilityDueToAgency_6E60BECE539BDA59539A8137D92BAAF0" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_HealthCareReformPremiumDeficiencyReserve" xlink:label="loc_moh_HealthCareReformPremiumDeficiencyReserve_588B00952327AA5E45298137D92BD9D2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_32ADD2A3E259456DCE068137D92A1EFA" xlink:to="loc_moh_HealthCareReformPremiumDeficiencyReserve_588B00952327AA5E45298137D92BD9D2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_54538AA1F30AD8F72B158137D92B1ACB" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_32ADD2A3E259456DCE068137D92A1EFA" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_54538AA1F30AD8F72B158137D92B1ACB" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SignificantAccountingPoliciesPolicies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SignificantAccountingPoliciesQualityIncentivePremiumRevenueRecognizedDetails" xlink:type="extended">
    <link:loc xlink:href="moh-20170630.xsd#moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems" xlink:label="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_76AC2782D0B8B0B0AAE98137D91A8F04" xlink:type="locator" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable" xlink:label="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_CA1AB462A15441B157158137D9196D20" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_76AC2782D0B8B0B0AAE98137D91A8F04" xlink:to="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_CA1AB462A15441B157158137D9196D20" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_37EFB2808B6A4401FC398137D919B338" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_CA1AB462A15441B157158137D9196D20" xlink:to="loc_us-gaap_RangeAxis_37EFB2808B6A4401FC398137D919B338" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_540B55651FE811DCBD318137D9199113_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_37EFB2808B6A4401FC398137D919B338" xlink:to="loc_us-gaap_RangeMember_540B55651FE811DCBD318137D9199113_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_540B55651FE811DCBD318137D9199113" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_37EFB2808B6A4401FC398137D919B338" xlink:to="loc_us-gaap_RangeMember_540B55651FE811DCBD318137D9199113" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_6DA5011BC2A8BF39AED78137D91A38C6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_540B55651FE811DCBD318137D9199113" xlink:to="loc_us-gaap_MinimumMember_6DA5011BC2A8BF39AED78137D91A38C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_834EDD3473AFFBFFC3CB8137D91A57CE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_540B55651FE811DCBD318137D9199113" xlink:to="loc_us-gaap_MaximumMember_834EDD3473AFFBFFC3CB8137D91A57CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_E9D80130E80EAD2C11E38137D91A0CA1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeTable_CA1AB462A15441B157158137D9196D20" xlink:to="loc_us-gaap_StatementGeographicalAxis_E9D80130E80EAD2C11E38137D91A0CA1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_8D848585655B7791DB238137D91AEDD4_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_E9D80130E80EAD2C11E38137D91A0CA1" xlink:to="loc_us-gaap_SegmentGeographicalDomain_8D848585655B7791DB238137D91AEDD4_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_8D848585655B7791DB238137D91AEDD4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementGeographicalAxis_E9D80130E80EAD2C11E38137D91A0CA1" xlink:to="loc_us-gaap_SegmentGeographicalDomain_8D848585655B7791DB238137D91AEDD4" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_CaliforniaIllinoisNewMexicoOhioSouthCarolinaTexasWashingtonandWisconsinMember" xlink:label="loc_moh_CaliforniaIllinoisNewMexicoOhioSouthCarolinaTexasWashingtonandWisconsinMember_2982D3AE8B7C83A88EB78137D91A4C73" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_8D848585655B7791DB238137D91AEDD4" xlink:to="loc_moh_CaliforniaIllinoisNewMexicoOhioSouthCarolinaTexasWashingtonandWisconsinMember_2982D3AE8B7C83A88EB78137D91A4C73" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_PercentageOfAdditionalIncrementalRevenueEarned" xlink:label="loc_moh_PercentageOfAdditionalIncrementalRevenueEarned_2C327F5DC573DA49DE7B8137D91AE30A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_76AC2782D0B8B0B0AAE98137D91A8F04" xlink:to="loc_moh_PercentageOfAdditionalIncrementalRevenueEarned_2C327F5DC573DA49DE7B8137D91AE30A" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MaximumAvailableQualityIncentivePremiumCurrentYear" xlink:label="loc_moh_MaximumAvailableQualityIncentivePremiumCurrentYear_06A9BA0F47953EC91A8F8137D91BBB1F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_76AC2782D0B8B0B0AAE98137D91A8F04" xlink:to="loc_moh_MaximumAvailableQualityIncentivePremiumCurrentYear_06A9BA0F47953EC91A8F8137D91BBB1F" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_QualityIncentivePremiumRevenueRecognizedAbstract" xlink:label="loc_moh_QualityIncentivePremiumRevenueRecognizedAbstract_DBDDBD1D3F93065064C98137D91B946E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_76AC2782D0B8B0B0AAE98137D91A8F04" xlink:to="loc_moh_QualityIncentivePremiumRevenueRecognizedAbstract_DBDDBD1D3F93065064C98137D91B946E" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_AmountOfCurrentYearQualityIncentivePremiumRevenueRecognized" xlink:label="loc_moh_AmountOfCurrentYearQualityIncentivePremiumRevenueRecognized_41CC5685F97827B924F48137D91BD220" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_QualityIncentivePremiumRevenueRecognizedAbstract_DBDDBD1D3F93065064C98137D91B946E" xlink:to="loc_moh_AmountOfCurrentYearQualityIncentivePremiumRevenueRecognized_41CC5685F97827B924F48137D91BD220" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_AmountOfQualityIncentivePremiumRevenueRecognizedFromPriorYear" xlink:label="loc_moh_AmountOfQualityIncentivePremiumRevenueRecognizedFromPriorYear_E79AA9F82668BD454AFB8137D91BEDAA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_QualityIncentivePremiumRevenueRecognizedAbstract_DBDDBD1D3F93065064C98137D91B946E" xlink:to="loc_moh_AmountOfQualityIncentivePremiumRevenueRecognizedFromPriorYear_E79AA9F82668BD454AFB8137D91BEDAA" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_QualityIncentivePremiumRevenueRecognized" xlink:label="loc_moh_QualityIncentivePremiumRevenueRecognized_073442E75550AADF22748137D91B1C68" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_QualityIncentivePremiumRevenueRecognizedAbstract_DBDDBD1D3F93065064C98137D91B946E" xlink:to="loc_moh_QualityIncentivePremiumRevenueRecognized_073442E75550AADF22748137D91B1C68" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_QualityIncentivePremiumRevenueAsAPercentageOfTotalRevenue" xlink:label="loc_moh_QualityIncentivePremiumRevenueAsAPercentageOfTotalRevenue_846ACF2FF89D2A9093D08137D91BC357" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_moh_ScheduleOfPremiumRevenueByHealthPlanTypeLineItems_76AC2782D0B8B0B0AAE98137D91A8F04" xlink:to="loc_moh_QualityIncentivePremiumRevenueAsAPercentageOfTotalRevenue_846ACF2FF89D2A9093D08137D91BC357" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SignificantAccountingPoliciesTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/StockholdersEquity" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/StockholdersEquityAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_5B403A5A5345912564019A494D554832" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_5B403A5A5345912564019A494D554832" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_7B68149411473BFDBD079A494D55C1AF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_5B403A5A5345912564019A494D554832" xlink:to="loc_us-gaap_StatementClassOfStockAxis_7B68149411473BFDBD079A494D55C1AF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_439CAF0AEE8F5019BDBB9A494D55A7E7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_7B68149411473BFDBD079A494D55C1AF" xlink:to="loc_us-gaap_ClassOfStockDomain_439CAF0AEE8F5019BDBB9A494D55A7E7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_439CAF0AEE8F5019BDBB9A494D55A7E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_7B68149411473BFDBD079A494D55C1AF" xlink:to="loc_us-gaap_ClassOfStockDomain_439CAF0AEE8F5019BDBB9A494D55A7E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_4DD508452BF4C13A682B9A494D568FD2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_439CAF0AEE8F5019BDBB9A494D55A7E7" xlink:to="loc_us-gaap_CommonStockMember_4DD508452BF4C13A682B9A494D568FD2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_C2D980DD3728144471159A494D56F8B6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_5B403A5A5345912564019A494D554832" xlink:to="loc_us-gaap_AwardTypeAxis_C2D980DD3728144471159A494D56F8B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_918766254915FF2B1A409A494D566A9B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_C2D980DD3728144471159A494D56F8B6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_918766254915FF2B1A409A494D566A9B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_918766254915FF2B1A409A494D566A9B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_C2D980DD3728144471159A494D56F8B6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_918766254915FF2B1A409A494D566A9B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_F40E750E9CC94EC3F6109A494D5623BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_918766254915FF2B1A409A494D566A9B" xlink:to="loc_us-gaap_RestrictedStockMember_F40E750E9CC94EC3F6109A494D5623BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaap_PerformanceSharesMember_69A1F7B57FB9C8267EC19A494D56737A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_918766254915FF2B1A409A494D566A9B" xlink:to="loc_us-gaap_PerformanceSharesMember_69A1F7B57FB9C8267EC19A494D56737A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_00844844B5730D2F8B0B9A494D569ACC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_918766254915FF2B1A409A494D566A9B" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_00844844B5730D2F8B0B9A494D569ACC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquityPeriodIncreaseDecrease" xlink:label="loc_us-gaap_StockholdersEquityPeriodIncreaseDecrease_6E5F14D51F34862D3F919A494D56083C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_StockholdersEquityPeriodIncreaseDecrease_6E5F14D51F34862D3F919A494D56083C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_64CC9941A1B2AE8DEDD09A494D5B41AC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_NetIncomeLoss_64CC9941A1B2AE8DEDD09A494D5B41AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_2465203B93FED500C40A9A50A53FCCE5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_2465203B93FED500C40A9A50A53FCCE5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtConversionConvertedInstrumentWarrantsOrOptionsIssued1" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentWarrantsOrOptionsIssued1_6360AA68A4FEFE1A36AA9A494D5B1CA0" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_DebtConversionConvertedInstrumentWarrantsOrOptionsIssued1_6360AA68A4FEFE1A36AA9A494D5B1CA0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_4B12820015BE958A54079A494D5B99F5" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_4B12820015BE958A54079A494D5B99F5" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ClassOfWarrantOrRightStatedPercentage" xlink:label="loc_moh_ClassOfWarrantOrRightStatedPercentage_CD904EF40B5ECC5682849A494D5BB7FA" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_moh_ClassOfWarrantOrRightStatedPercentage_CD904EF40B5ECC5682849A494D5BB7FA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_1A9A7A8380837EE0061E9A494D5C7594" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_1A9A7A8380837EE0061E9A494D5C7594" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantedInPeriodFairValue" xlink:label="loc_moh_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantedInPeriodFairValue_6E68349C97AAA67999289A494D5C63BE" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_moh_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantedInPeriodFairValue_6E68349C97AAA67999289A494D5C63BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_957BF5A08D9340564BA49A494D5CF9EB" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_957BF5A08D9340564BA49A494D5CF9EB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber_452D7975A5ECD5CBD9129A494D5CF99D" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber_452D7975A5ECD5CBD9129A494D5CF99D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_1B83FBEF39D32BAE789F9A494D5CCEF7" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_1B83FBEF39D32BAE789F9A494D5CCEF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAcceleratedCompensationCost" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAcceleratedCompensationCost_DEA88D7E431E0CA523CE9A494D5C427F" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAcceleratedCompensationCost_DEA88D7E431E0CA523CE9A494D5C427F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_545CFFFA8F39D8E6758E9A494D5C9794" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_545CFFFA8F39D8E6758E9A494D5C9794" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_F768BA161F684C0647D39A494D5C8E2F" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_F768BA161F684C0647D39A494D5C8E2F" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_UnrecognizedCompensationForfeitedRate" xlink:label="loc_moh_UnrecognizedCompensationForfeitedRate_862CBD556A6DF85D9C999A494D5C2D49" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_AC25D38D696DDA679B029A494D560BFB" xlink:to="loc_moh_UnrecognizedCompensationForfeitedRate_862CBD556A6DF85D9C999A494D5C2D49" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/StockholdersEquityShareActivityDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems_98217E529E25F8E64A438137D84EAF55" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualShareBasedPaymentsTable" xlink:label="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualShareBasedPaymentsTable_4D24EFD15B42274D4E8A8137D84DE0F2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems_98217E529E25F8E64A438137D84EAF55" xlink:to="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualShareBasedPaymentsTable_4D24EFD15B42274D4E8A8137D84DE0F2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_147F11DE2D9DF63A3D498137D84DC2A8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualShareBasedPaymentsTable_4D24EFD15B42274D4E8A8137D84DE0F2" xlink:to="loc_us-gaap_AwardTypeAxis_147F11DE2D9DF63A3D498137D84DC2A8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1C03002BC8017C9DB2C28137D84D0A9A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_147F11DE2D9DF63A3D498137D84DC2A8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1C03002BC8017C9DB2C28137D84D0A9A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1C03002BC8017C9DB2C28137D84D0A9A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_147F11DE2D9DF63A3D498137D84DC2A8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1C03002BC8017C9DB2C28137D84D0A9A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_2A8B67495677A51DAA318137D84E1AE0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1C03002BC8017C9DB2C28137D84D0A9A" xlink:to="loc_us-gaap_RestrictedStockMember_2A8B67495677A51DAA318137D84E1AE0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PerformanceSharesMember" xlink:label="loc_us-gaap_PerformanceSharesMember_59647A79EF5A17408CF38137D84EB5E7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1C03002BC8017C9DB2C28137D84D0A9A" xlink:to="loc_us-gaap_PerformanceSharesMember_59647A79EF5A17408CF38137D84EB5E7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_8DA4CA1F6008CEEB73668137D84EF342" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1C03002BC8017C9DB2C28137D84D0A9A" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_8DA4CA1F6008CEEB73668137D84EF342" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_1DD0AE55B8970235B77F8137D84FB438" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems_98217E529E25F8E64A438137D84EAF55" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_1DD0AE55B8970235B77F8137D84FB438" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_6D4473FDB3C65A9E170C8137D84FFAB6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_1DD0AE55B8970235B77F8137D84FB438" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_6D4473FDB3C65A9E170C8137D84FFAB6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3A9771A0E15022E8C4488137D84F79CA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_1DD0AE55B8970235B77F8137D84FB438" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3A9771A0E15022E8C4488137D84F79CA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4E2DFCE1176EF06A26BF8137D84F2427" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_1DD0AE55B8970235B77F8137D84FB438" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4E2DFCE1176EF06A26BF8137D84F2427" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_5EEDB769107C8D4A38F88137D84F539F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_1DD0AE55B8970235B77F8137D84FB438" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_5EEDB769107C8D4A38F88137D84F539F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A8E35D90D0E219EC3F128137D8509B81" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems_98217E529E25F8E64A438137D84EAF55" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A8E35D90D0E219EC3F128137D8509B81" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_3664B37D614C4D9E9BE18137D850D2BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A8E35D90D0E219EC3F128137D8509B81" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_3664B37D614C4D9E9BE18137D850D2BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_02FB62D19C622ED558578137D850F089" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A8E35D90D0E219EC3F128137D8509B81" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_02FB62D19C622ED558578137D850F089" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_2DE359AD6BF1097D6D238137D8504390" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A8E35D90D0E219EC3F128137D8509B81" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_2DE359AD6BF1097D6D238137D8504390" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_FB586F2F06EFBFEC7A3F8137D851DFF9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_A8E35D90D0E219EC3F128137D8509B81" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_FB586F2F06EFBFEC7A3F8137D851DFF9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/StockholdersEquityTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformation" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedFinancialStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_CA593E43625B35A86C6A8137D79CA4E4" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfCondensedFinancialStatementsTable" xlink:label="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_73E37669076F2F9DC7FD8137D79B2C0B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_CA593E43625B35A86C6A8137D79CA4E4" xlink:to="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_73E37669076F2F9DC7FD8137D79B2C0B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_15D2FBEC22ABCC32575B8137D79B0B13" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_73E37669076F2F9DC7FD8137D79B2C0B" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_15D2FBEC22ABCC32575B8137D79B0B13" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_C00E0A5F6A6EE1ED3AC08137D79B4B50_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_15D2FBEC22ABCC32575B8137D79B0B13" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_C00E0A5F6A6EE1ED3AC08137D79B4B50_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_C00E0A5F6A6EE1ED3AC08137D79B4B50" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_15D2FBEC22ABCC32575B8137D79B0B13" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_C00E0A5F6A6EE1ED3AC08137D79B4B50" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="loc_us-gaap_SeniorNotesMember_D152AE2977ED414263998137D79B50E5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_C00E0A5F6A6EE1ED3AC08137D79B4B50" xlink:to="loc_us-gaap_SeniorNotesMember_D152AE2977ED414263998137D79B50E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_4B694C181B5EFC5B006A8137D79B36B7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCondensedFinancialStatementsTable_73E37669076F2F9DC7FD8137D79B2C0B" xlink:to="loc_us-gaap_DebtInstrumentAxis_4B694C181B5EFC5B006A8137D79B36B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_21B146A4ABE27E7E017E8137D79C446A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_4B694C181B5EFC5B006A8137D79B36B7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_21B146A4ABE27E7E017E8137D79C446A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_21B146A4ABE27E7E017E8137D79C446A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_4B694C181B5EFC5B006A8137D79B36B7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_21B146A4ABE27E7E017E8137D79C446A" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_SeniorNotesDue2022Member" xlink:label="loc_moh_SeniorNotesDue2022Member_19F4215803CC24643F9C8137D79C3C34" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_21B146A4ABE27E7E017E8137D79C446A" xlink:to="loc_moh_SeniorNotesDue2022Member_19F4215803CC24643F9C8137D79C3C34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_1B1F611D68DA112A4C298137D79C840E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedFinancialStatementsCaptionsLineItems_CA593E43625B35A86C6A8137D79CA4E4" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_1B1F611D68DA112A4C298137D79C840E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationBalanceSheetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_F7A5E9281A1B2E31CFFB85D5687E471A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedBalanceSheetStatementTable" xlink:label="loc_us-gaap_CondensedBalanceSheetStatementTable_8E1E45CA4AC56F8A6EFE85D5687B701F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_F7A5E9281A1B2E31CFFB85D5687E471A" xlink:to="loc_us-gaap_CondensedBalanceSheetStatementTable_8E1E45CA4AC56F8A6EFE85D5687B701F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_EC48B81A6C25A82EB69C85D5687C60D9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementTable_8E1E45CA4AC56F8A6EFE85D5687B701F" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_EC48B81A6C25A82EB69C85D5687C60D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_813B3E3B0A771B8DC60B85D5687DD88A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_EC48B81A6C25A82EB69C85D5687C60D9" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_813B3E3B0A771B8DC60B85D5687DD88A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_813B3E3B0A771B8DC60B85D5687DD88A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_EC48B81A6C25A82EB69C85D5687C60D9" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_813B3E3B0A771B8DC60B85D5687DD88A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_C9A45B39755A45340E2785D5687D4AB7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_813B3E3B0A771B8DC60B85D5687DD88A" xlink:to="loc_us-gaap_ParentCompanyMember_C9A45B39755A45340E2785D5687D4AB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_7D15F1EC2DAB00172EB885D5687D5C91" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_813B3E3B0A771B8DC60B85D5687DD88A" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_7D15F1EC2DAB00172EB885D5687D5C91" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_626B10658DB8BCD13D1285D5687DD6F2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_813B3E3B0A771B8DC60B85D5687DD88A" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_626B10658DB8BCD13D1285D5687DD6F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_A7B97554E83B3310316B85D5687DAF69" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementTable_8E1E45CA4AC56F8A6EFE85D5687B701F" xlink:to="loc_us-gaap_ConsolidationItemsAxis_A7B97554E83B3310316B85D5687DAF69" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_CE8335520497F3EBC09785D5687DEBFF_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_A7B97554E83B3310316B85D5687DAF69" xlink:to="loc_us-gaap_ConsolidationItemsDomain_CE8335520497F3EBC09785D5687DEBFF_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_CE8335520497F3EBC09785D5687DEBFF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_A7B97554E83B3310316B85D5687DAF69" xlink:to="loc_us-gaap_ConsolidationItemsDomain_CE8335520497F3EBC09785D5687DEBFF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_5251B7E2D717A135A84B85D5687E42DC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_CE8335520497F3EBC09785D5687DEBFF" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_5251B7E2D717A135A84B85D5687E42DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReportableLegalEntitiesMember" xlink:label="loc_us-gaap_ReportableLegalEntitiesMember_53EC6E2C5B5BA5FE683185D5687EF0F1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_CE8335520497F3EBC09785D5687DEBFF" xlink:to="loc_us-gaap_ReportableLegalEntitiesMember_53EC6E2C5B5BA5FE683185D5687EF0F1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_F7A5E9281A1B2E31CFFB85D5687E471A" xlink:to="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:to="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_C9620ECB0E4C44064D9F85D5687E9108" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_C9620ECB0E4C44064D9F85D5687E9108" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_MarketableSecuritiesCurrent" xlink:label="loc_us-gaap_MarketableSecuritiesCurrent_37362CF359C1B8DFC42C85D5687F2975" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:to="loc_us-gaap_MarketableSecuritiesCurrent_37362CF359C1B8DFC42C85D5687F2975" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedInvestmentsCurrent" xlink:label="loc_us-gaap_RestrictedInvestmentsCurrent_244536E5668042A5286185D5687FAA1A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:to="loc_us-gaap_RestrictedInvestmentsCurrent_244536E5668042A5286185D5687FAA1A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReceivablesNetCurrent" xlink:label="loc_us-gaap_ReceivablesNetCurrent_EC7B3317640CA23D22D685D5687F9AC4" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:to="loc_us-gaap_ReceivablesNetCurrent_EC7B3317640CA23D22D685D5687F9AC4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxesReceivable" xlink:label="loc_us-gaap_IncomeTaxesReceivable_6398CF4B2F0A0EE1B98285D5687F194F" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:to="loc_us-gaap_IncomeTaxesReceivable_6398CF4B2F0A0EE1B98285D5687F194F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RelatedPartyTransactionDueFromToRelatedPartyCurrent" xlink:label="loc_us-gaap_RelatedPartyTransactionDueFromToRelatedPartyCurrent_B6B9EA544B4F204D3ECB85D5687F18C0" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:to="loc_us-gaap_RelatedPartyTransactionDueFromToRelatedPartyCurrent_B6B9EA544B4F204D3ECB85D5687F18C0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_D9DA9EAB3BAB42CAF69985D56880BAEB" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_D9DA9EAB3BAB42CAF69985D56880BAEB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeAssetsCurrent" xlink:label="loc_us-gaap_DerivativeAssetsCurrent_58A330013183F4B59C9385D56880A2E2" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:to="loc_us-gaap_DerivativeAssetsCurrent_58A330013183F4B59C9385D56880A2E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent_57855EBB34B5F763BDB185D568803A7A" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsCurrentAbstract_134E95026F55BF43490885D5687E3590" xlink:to="loc_us-gaap_AssetsCurrent_57855EBB34B5F763BDB185D568803A7A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_25BE83461FE93098C08B85D56880974D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_25BE83461FE93098C08B85D56880974D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedAfterOneYear" xlink:label="loc_us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedAfterOneYear_8FF20EBC88D9F2D3610685D56881E411" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:to="loc_us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrProgramsExpectedToBeCollectedAfterOneYear_8FF20EBC88D9F2D3610685D56881E411" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetIncludingGoodwill_F98A3F2AF6F0D84D8DD685D56881A2AC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:to="loc_us-gaap_IntangibleAssetsNetIncludingGoodwill_F98A3F2AF6F0D84D8DD685D56881A2AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestrictedInvestmentsNoncurrent" xlink:label="loc_us-gaap_RestrictedInvestmentsNoncurrent_E9C339E0681D872E78F785D56881D638" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:to="loc_us-gaap_RestrictedInvestmentsNoncurrent_E9C339E0681D872E78F785D56881D638" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_95EC28125B09A90621B085D568811EA8" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_95EC28125B09A90621B085D568811EA8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_361B29A5BAACE6BECC1185D5688158D6" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_361B29A5BAACE6BECC1185D5688158D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_2DF9298DC5383499F06A85D568815E03" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_2DF9298DC5383499F06A85D568815E03" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_8A27DB40931538E791D585D56881E0DF" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_032F0530691270C20B2885D5687E6B8F" xlink:to="loc_us-gaap_Assets_8A27DB40931538E791D585D56881E0DF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8BCB6830033FB7549C7D85D568813E2A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedBalanceSheetStatementsCaptionsLineItems_F7A5E9281A1B2E31CFFB85D5687E471A" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8BCB6830033FB7549C7D85D568813E2A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_49ADE66AC0D16AF9799F85D56882E3D6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8BCB6830033FB7549C7D85D568813E2A" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_49ADE66AC0D16AF9799F85D56882E3D6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense_778CF5ECE503AF53C12885D568829DE5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_49ADE66AC0D16AF9799F85D56882E3D6" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense_778CF5ECE503AF53C12885D568829DE5" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_MedicalPremiumLiabilityDueToAgency" xlink:label="loc_moh_MedicalPremiumLiabilityDueToAgency_705C472692AB4C0882D285D56882966C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_49ADE66AC0D16AF9799F85D56882E3D6" xlink:to="loc_moh_MedicalPremiumLiabilityDueToAgency_705C472692AB4C0882D285D56882966C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_BD21849E1560B76C825985D56882F3BE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_49ADE66AC0D16AF9799F85D56882E3D6" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_BD21849E1560B76C825985D56882F3BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredRevenueCurrent" xlink:label="loc_us-gaap_DeferredRevenueCurrent_9ED904028FDC6CD8FDC485D568821C86" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_49ADE66AC0D16AF9799F85D56882E3D6" xlink:to="loc_us-gaap_DeferredRevenueCurrent_9ED904028FDC6CD8FDC485D568821C86" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_E6AA5CC4500D5B764D18861B715D349E" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_49ADE66AC0D16AF9799F85D56882E3D6" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_E6AA5CC4500D5B764D18861B715D349E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DerivativeLiabilitiesCurrent" xlink:label="loc_us-gaap_DerivativeLiabilitiesCurrent_F3C78C565C5417B9C1DC85D568821B1B" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_49ADE66AC0D16AF9799F85D56882E3D6" xlink:to="loc_us-gaap_DerivativeLiabilitiesCurrent_F3C78C565C5417B9C1DC85D568821B1B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent_5A8EB3FE7E27AEE1472D85D568821DC8" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_49ADE66AC0D16AF9799F85D56882E3D6" xlink:to="loc_us-gaap_LiabilitiesCurrent_5A8EB3FE7E27AEE1472D85D568821DC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_4A439A3BACF96C4D4D1885D56883073A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8BCB6830033FB7549C7D85D568813E2A" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_4A439A3BACF96C4D4D1885D56883073A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_C9E0CBEB04E73432553985D568834126" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8BCB6830033FB7549C7D85D568813E2A" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesNoncurrent_C9E0CBEB04E73432553985D568834126" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_EC2C7E7212D92C69F9B285D56883EAB5" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8BCB6830033FB7549C7D85D568813E2A" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_EC2C7E7212D92C69F9B285D56883EAB5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities_E3D7922525DB5B79B70585D56883E668" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8BCB6830033FB7549C7D85D568813E2A" xlink:to="loc_us-gaap_Liabilities_E3D7922525DB5B79B70585D56883E668" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_E40CCF83D554AFA98E3385D568830BE4" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8BCB6830033FB7549C7D85D568813E2A" xlink:to="loc_us-gaap_StockholdersEquity_E40CCF83D554AFA98E3385D568830BE4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_5D3C01ACE68BB39D044085D56883EEB5" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_8BCB6830033FB7549C7D85D568813E2A" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_5D3C01ACE68BB39D044085D56883EEB5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationCashFlowsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedCashFlowStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_5EDBC0AA605608EC38B395E619BCBEEF" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedCashFlowStatementTable" xlink:label="loc_us-gaap_CondensedCashFlowStatementTable_1524AAF29802B10CC92D95E619BB76CF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_5EDBC0AA605608EC38B395E619BCBEEF" xlink:to="loc_us-gaap_CondensedCashFlowStatementTable_1524AAF29802B10CC92D95E619BB76CF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_D3190EEC16D62F52512895E619BBD93E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_1524AAF29802B10CC92D95E619BB76CF" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_D3190EEC16D62F52512895E619BBD93E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_CCD858A2839B9840DA4D95E619BB36B5_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_D3190EEC16D62F52512895E619BBD93E" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_CCD858A2839B9840DA4D95E619BB36B5_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_CCD858A2839B9840DA4D95E619BB36B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_D3190EEC16D62F52512895E619BBD93E" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_CCD858A2839B9840DA4D95E619BB36B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_78BB89FA5BE1517053F995E619BB357F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_CCD858A2839B9840DA4D95E619BB36B5" xlink:to="loc_us-gaap_ParentCompanyMember_78BB89FA5BE1517053F995E619BB357F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_7B005EB7C37E1D78951D95E619BB84CB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_CCD858A2839B9840DA4D95E619BB36B5" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_7B005EB7C37E1D78951D95E619BB84CB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_597BD874190F43CEEEBE95E619BB23F2" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_CCD858A2839B9840DA4D95E619BB36B5" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_597BD874190F43CEEEBE95E619BB23F2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_51C7C2931ECE6BCD23DE95E619BBFC99" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedCashFlowStatementTable_1524AAF29802B10CC92D95E619BB76CF" xlink:to="loc_us-gaap_ConsolidationItemsAxis_51C7C2931ECE6BCD23DE95E619BBFC99" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_D5E52AED22927DEA6E1B95E619BBC1B3_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_51C7C2931ECE6BCD23DE95E619BBFC99" xlink:to="loc_us-gaap_ConsolidationItemsDomain_D5E52AED22927DEA6E1B95E619BBC1B3_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_D5E52AED22927DEA6E1B95E619BBC1B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_51C7C2931ECE6BCD23DE95E619BBFC99" xlink:to="loc_us-gaap_ConsolidationItemsDomain_D5E52AED22927DEA6E1B95E619BBC1B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReportableLegalEntitiesMember" xlink:label="loc_us-gaap_ReportableLegalEntitiesMember_A9FFE91168109B75001195E619BBCAE1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_D5E52AED22927DEA6E1B95E619BBC1B3" xlink:to="loc_us-gaap_ReportableLegalEntitiesMember_A9FFE91168109B75001195E619BBCAE1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_F87D8CB803B29F4A022A95E619BBF399" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_D5E52AED22927DEA6E1B95E619BBC1B3" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_F87D8CB803B29F4A022A95E619BBF399" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_539DD5DCD6304676A2E195E619BCFC49" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_5EDBC0AA605608EC38B395E619BCBEEF" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_539DD5DCD6304676A2E195E619BCFC49" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_97CCECF32C98DD7047A795E619BC4711" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_539DD5DCD6304676A2E195E619BCFC49" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_97CCECF32C98DD7047A795E619BC4711" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_5EDBC0AA605608EC38B395E619BCBEEF" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireMarketableSecurities" xlink:label="loc_us-gaap_PaymentsToAcquireMarketableSecurities_165075E090457DAABE0E95E619BC6E7C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_us-gaap_PaymentsToAcquireMarketableSecurities_165075E090457DAABE0E95E619BC6E7C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities" xlink:label="loc_us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_95ACD96C165B6B10D7AC95E619BC55FD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_95ACD96C165B6B10D7AC95E619BC55FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_7B4074441C0DFDC31C7995E619BCC2CF" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_7B4074441C0DFDC31C7995E619BCC2CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncreaseDecreaseOfRestrictedInvestments" xlink:label="loc_us-gaap_IncreaseDecreaseOfRestrictedInvestments_505FDFB59967C8584A9895E619BCADA9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_us-gaap_IncreaseDecreaseOfRestrictedInvestments_505FDFB59967C8584A9895E619BCADA9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_EBEAAFFB4FBB042A003695E619BC366C" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_EBEAAFFB4FBB042A003695E619BC366C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries" xlink:label="loc_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries_EFAD3B9AB01257E8698F95E619BDDDBB" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries_EFAD3B9AB01257E8698F95E619BDDDBB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromDividendsReceived" xlink:label="loc_us-gaap_ProceedsFromDividendsReceived_F57475CC5358E86991A395E619BD0F9D" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_us-gaap_ProceedsFromDividendsReceived_F57475CC5358E86991A395E619BD0F9D" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_ChangesInAmountsDueToAndDueFromAffiliates" xlink:label="loc_moh_ChangesInAmountsDueToAndDueFromAffiliates_2F21BA99B7DCF52BFC6395E619BD755F" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_moh_ChangesInAmountsDueToAndDueFromAffiliates_2F21BA99B7DCF52BFC6395E619BD755F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_B8AEB44C15F40A6E072395E619BD3ADC" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_B8AEB44C15F40A6E072395E619BD3ADC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_A531329A0A489DF0618995E619BD96A6" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_253D46E82666E9C4B99E95E619BC6C62" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_A531329A0A489DF0618995E619BD96A6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_F562A7B355FC0ECEF17595E619BD7ADA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_5EDBC0AA605608EC38B395E619BCBEEF" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_F562A7B355FC0ECEF17595E619BD7ADA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromDebtNetOfIssuanceCosts" xlink:label="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_14506F79EB72C48A10BC95E619BD7417" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_F562A7B355FC0ECEF17595E619BD7ADA" xlink:to="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_14506F79EB72C48A10BC95E619BD7417" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_2304623DD243EABD390695E619BDE38A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_F562A7B355FC0ECEF17595E619BD7ADA" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_2304623DD243EABD390695E619BDE38A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" xlink:label="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_FC8F7EFD2BA33481587F95E619BE26C6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_F562A7B355FC0ECEF17595E619BD7ADA" xlink:to="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_FC8F7EFD2BA33481587F95E619BE26C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_13DD12B56EF58F592F2695E619BE1622" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_F562A7B355FC0ECEF17595E619BD7ADA" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_13DD12B56EF58F592F2695E619BE1622" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_2DE1F97EE0A472FBDE9F95E619BE1233" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_5EDBC0AA605608EC38B395E619BCBEEF" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_2DE1F97EE0A472FBDE9F95E619BE1233" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_3CEC4667D17F8CA0E79995E619BEB80B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedCashFlowStatementsCaptionsLineItems_5EDBC0AA605608EC38B395E619BCBEEF" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_3CEC4667D17F8CA0E79995E619BEB80B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationComprehensiveIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedStatementOfIncomeCaptionsLineItems" xlink:label="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_39B89C4EEC11A25B5A27852F1292CC78" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedStatementOfComprehensiveIncomeTable" xlink:label="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_9D550EE50A98B99BBDA5852F129125C4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_39B89C4EEC11A25B5A27852F1292CC78" xlink:to="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_9D550EE50A98B99BBDA5852F129125C4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_8133B4AAF40C40F16B5B852F1291B497" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_9D550EE50A98B99BBDA5852F129125C4" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_8133B4AAF40C40F16B5B852F1291B497" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_85B24F9CEBF28453278C852F12926399_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_8133B4AAF40C40F16B5B852F1291B497" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_85B24F9CEBF28453278C852F12926399_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_85B24F9CEBF28453278C852F12926399" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_8133B4AAF40C40F16B5B852F1291B497" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_85B24F9CEBF28453278C852F12926399" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_B61541344AC1B0708E04852F12923971" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_85B24F9CEBF28453278C852F12926399" xlink:to="loc_us-gaap_ParentCompanyMember_B61541344AC1B0708E04852F12923971" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_5B930A1C37B7E4EA12C4852F12920A69" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_85B24F9CEBF28453278C852F12926399" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_5B930A1C37B7E4EA12C4852F12920A69" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_076E244186F49C617859852F12921083" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_85B24F9CEBF28453278C852F12926399" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_076E244186F49C617859852F12921083" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_AEB0C6AA99668833E76F852F12923CD0" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedStatementOfComprehensiveIncomeTable_9D550EE50A98B99BBDA5852F129125C4" xlink:to="loc_us-gaap_ConsolidationItemsAxis_AEB0C6AA99668833E76F852F12923CD0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_9D35F67C3AE831FABBD0852F1292806E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_AEB0C6AA99668833E76F852F12923CD0" xlink:to="loc_us-gaap_ConsolidationItemsDomain_9D35F67C3AE831FABBD0852F1292806E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_9D35F67C3AE831FABBD0852F1292806E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_AEB0C6AA99668833E76F852F12923CD0" xlink:to="loc_us-gaap_ConsolidationItemsDomain_9D35F67C3AE831FABBD0852F1292806E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReportableLegalEntitiesMember" xlink:label="loc_us-gaap_ReportableLegalEntitiesMember_FE78D87B8A078C4DD8E4852F129220B2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_9D35F67C3AE831FABBD0852F1292806E" xlink:to="loc_us-gaap_ReportableLegalEntitiesMember_FE78D87B8A078C4DD8E4852F129220B2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_DAAA64D1BE1D2CAF4AB7852F12923D32" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_9D35F67C3AE831FABBD0852F1292806E" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_DAAA64D1BE1D2CAF4AB7852F12923D32" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_4C4489FB22D377C3C20D852F1292F820" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_39B89C4EEC11A25B5A27852F1292CC78" xlink:to="loc_us-gaap_NetIncomeLoss_4C4489FB22D377C3C20D852F1292F820" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_A25E8F2059EBD844BB55852F12930443" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_39B89C4EEC11A25B5A27852F1292CC78" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_A25E8F2059EBD844BB55852F12930443" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_2AC376CFF312F96CB0B9852F12937E70" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedStatementOfIncomeCaptionsLineItems_39B89C4EEC11A25B5A27852F1292CC78" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_2AC376CFF312F96CB0B9852F12937E70" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationStatementsOfOperationsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedIncomeStatementsCaptionsLineItems" xlink:label="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CondensedIncomeStatementTable" xlink:label="loc_us-gaap_CondensedIncomeStatementTable_9FA47288AC25042EC4F795E619E2A76D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_CondensedIncomeStatementTable_9FA47288AC25042EC4F795E619E2A76D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesAxis" xlink:label="loc_us-gaap_ConsolidatedEntitiesAxis_E45013E05EEC07A21DB795E619E2825B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedIncomeStatementTable_9FA47288AC25042EC4F795E619E2A76D" xlink:to="loc_us-gaap_ConsolidatedEntitiesAxis_E45013E05EEC07A21DB795E619E2825B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_4080AA3D9539EB25459495E619E28430_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_E45013E05EEC07A21DB795E619E2825B" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_4080AA3D9539EB25459495E619E28430_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidatedEntitiesDomain" xlink:label="loc_us-gaap_ConsolidatedEntitiesDomain_4080AA3D9539EB25459495E619E28430" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidatedEntitiesAxis_E45013E05EEC07A21DB795E619E2825B" xlink:to="loc_us-gaap_ConsolidatedEntitiesDomain_4080AA3D9539EB25459495E619E28430" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="loc_us-gaap_ParentCompanyMember_81B085ABDBD5C7ADA9AA95E619E2B645" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_4080AA3D9539EB25459495E619E28430" xlink:to="loc_us-gaap_ParentCompanyMember_81B085ABDBD5C7ADA9AA95E619E2B645" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GuarantorSubsidiariesMember" xlink:label="loc_us-gaap_GuarantorSubsidiariesMember_A833269397E40DEDBDDE95E619E3C713" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_4080AA3D9539EB25459495E619E28430" xlink:to="loc_us-gaap_GuarantorSubsidiariesMember_A833269397E40DEDBDDE95E619E3C713" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NonGuarantorSubsidiariesMember" xlink:label="loc_us-gaap_NonGuarantorSubsidiariesMember_16E68D69AD2AFDE6261795E619E3D5AC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidatedEntitiesDomain_4080AA3D9539EB25459495E619E28430" xlink:to="loc_us-gaap_NonGuarantorSubsidiariesMember_16E68D69AD2AFDE6261795E619E3D5AC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsAxis" xlink:label="loc_us-gaap_ConsolidationItemsAxis_B2CAA0BB5BEAADEC987695E619E36467" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CondensedIncomeStatementTable_9FA47288AC25042EC4F795E619E2A76D" xlink:to="loc_us-gaap_ConsolidationItemsAxis_B2CAA0BB5BEAADEC987695E619E36467" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_E0D371F04B2965F8040E95E619E30519_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConsolidationItemsAxis_B2CAA0BB5BEAADEC987695E619E36467" xlink:to="loc_us-gaap_ConsolidationItemsDomain_E0D371F04B2965F8040E95E619E30519_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationItemsDomain" xlink:label="loc_us-gaap_ConsolidationItemsDomain_E0D371F04B2965F8040E95E619E30519" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConsolidationItemsAxis_B2CAA0BB5BEAADEC987695E619E36467" xlink:to="loc_us-gaap_ConsolidationItemsDomain_E0D371F04B2965F8040E95E619E30519" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ReportableLegalEntitiesMember" xlink:label="loc_us-gaap_ReportableLegalEntitiesMember_A4D427DF10C483F1750C95E619E306B5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_E0D371F04B2965F8040E95E619E30519" xlink:to="loc_us-gaap_ReportableLegalEntitiesMember_A4D427DF10C483F1750C95E619E306B5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ConsolidationEliminationsMember" xlink:label="loc_us-gaap_ConsolidationEliminationsMember_A5975EE10DDD42BEC44895E619E30D9E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConsolidationItemsDomain_E0D371F04B2965F8040E95E619E30519" xlink:to="loc_us-gaap_ConsolidationEliminationsMember_A5975EE10DDD42BEC44895E619E30D9E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RevenuesAbstract" xlink:label="loc_us-gaap_RevenuesAbstract_93316ACD693F990F219395E619E34BAF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_RevenuesAbstract_93316ACD693F990F219395E619E34BAF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_FD72E4767EB83C70F85595E619E36207" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_93316ACD693F990F219395E619E34BAF" xlink:to="loc_us-gaap_Revenues_FD72E4767EB83C70F85595E619E36207" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpensesAbstract" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_PolicyholderBenefitsAndClaimsIncurredHealthCare" xlink:label="loc_us-gaap_PolicyholderBenefitsAndClaimsIncurredHealthCare_B2577D42A9BAE7EC6FF995E619E30551" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:to="loc_us-gaap_PolicyholderBenefitsAndClaimsIncurredHealthCare_B2577D42A9BAE7EC6FF995E619E30551" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_TechnologyServicesCosts" xlink:label="loc_us-gaap_TechnologyServicesCosts_C1920F7817BCCBE9D5AB95E619E496BE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:to="loc_us-gaap_TechnologyServicesCosts_C1920F7817BCCBE9D5AB95E619E496BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_007215CBA2C83DFB638495E619E46EBE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_007215CBA2C83DFB638495E619E46EBE" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_PremiumTaxExpenses" xlink:label="loc_moh_PremiumTaxExpenses_2313FE5240CC22EFAA2095E619E46724" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:to="loc_moh_PremiumTaxExpenses_2313FE5240CC22EFAA2095E619E46724" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_HealthCareOrganizationInsurerFeeExpense" xlink:label="loc_moh_HealthCareOrganizationInsurerFeeExpense_DFEB617D71DCECAD851995E619E4FAA6" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:to="loc_moh_HealthCareOrganizationInsurerFeeExpense_DFEB617D71DCECAD851995E619E4FAA6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="loc_us-gaap_DepreciationAndAmortization_6D9079EEBFE4E4407A6E95E619E4CB02" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:to="loc_us-gaap_DepreciationAndAmortization_6D9079EEBFE4E4407A6E95E619E4CB02" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetImpairment" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetImpairment_3950BBB3CFF9DD54B35D95EC6424709F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:to="loc_us-gaap_GoodwillAndIntangibleAssetImpairment_3950BBB3CFF9DD54B35D95EC6424709F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_RestructuringCosts" xlink:label="loc_us-gaap_RestructuringCosts_992599FC5254CE51956C95E619E4B4EF" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:to="loc_us-gaap_RestructuringCosts_992599FC5254CE51956C95E619E4B4EF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="loc_us-gaap_CostsAndExpenses_9C6B953B5FAD782C67F995E619E43084" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_30C66CA75FF0D5BC55FF95E619E32C5F" xlink:to="loc_us-gaap_CostsAndExpenses_9C6B953B5FAD782C67F995E619E43084" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_01345D2A7EBE4116482895E619E452E5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_OperatingIncomeLoss_01345D2A7EBE4116482895E619E452E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_7146FE7DC75EABC9F28C95E619E49329" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_InterestExpense_7146FE7DC75EABC9F28C95E619E49329" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_5C2A45410AE6CE91FD4E95E619E51D1D" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_5C2A45410AE6CE91FD4E95E619E51D1D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_AE6AB86138530ED72DAF95E619E52615" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_AE6AB86138530ED72DAF95E619E52615" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_BBA63E086E843950196C95E619E5F440" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_BBA63E086E843950196C95E619E5F440" xlink:type="arc" />
    <link:loc xlink:href="moh-20170630.xsd#moh_NetIncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_moh_NetIncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsExtraordinaryItemsNoncontrollingInterest_C6261F3AD90A998663D395E619E54731" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_moh_NetIncomeLossFromContinuingOperationsBeforeEquityMethodInvestmentsExtraordinaryItemsNoncontrollingInterest_C6261F3AD90A998663D395E619E54731" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_IncomeLossFromSubsidiariesNetOfTax" xlink:label="loc_us-gaap_IncomeLossFromSubsidiariesNetOfTax_28130CC6318D6039F3F495E619E5582C" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_IncomeLossFromSubsidiariesNetOfTax_28130CC6318D6039F3F495E619E5582C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_27CDE8BF3A90D56B660995E619E541DB" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CondensedIncomeStatementsCaptionsLineItems_7D0C16724CD93EBD0AB995E619E3F645" xlink:to="loc_us-gaap_NetIncomeLoss_27CDE8BF3A90D56B660995E619E541DB" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/SupplementalCondensedConsolidatingFinancialInformationTables" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/VariableInterestEntitiesVies" xlink:type="extended" />
  <link:definitionLink xlink:role="http://www.molinahealthcare.com/role/VariableInterestEntitiesViesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntityLineItems" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_C9DBF74C5B004F881B5B95E619F5AC88" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_F0AA7FF43E29167C811295E619F4FD23" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_C9DBF74C5B004F881B5B95E619F5AC88" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_F0AA7FF43E29167C811295E619F4FD23" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis" xlink:label="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_8064820400E176ED745295E619F4B006" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_F0AA7FF43E29167C811295E619F4FD23" xlink:to="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_8064820400E176ED745295E619F4B006" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_E13EF4DF9570DDFA5E2095E619F5F35E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_8064820400E176ED745295E619F4B006" xlink:to="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_E13EF4DF9570DDFA5E2095E619F5F35E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_E13EF4DF9570DDFA5E2095E619F5F35E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_8064820400E176ED745295E619F4B006" xlink:to="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_E13EF4DF9570DDFA5E2095E619F5F35E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntityPrimaryBeneficiaryMember" xlink:label="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_B4CEBB0706625F65CB3F95E619F5774A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_E13EF4DF9570DDFA5E2095E619F5F35E" xlink:to="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_B4CEBB0706625F65CB3F95E619F5774A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntityFinancialOrOtherSupportAmount" xlink:label="loc_us-gaap_VariableInterestEntityFinancialOrOtherSupportAmount_63BFBAB95F9B745E6DEC95E619F5B074" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_C9DBF74C5B004F881B5B95E619F5AC88" xlink:to="loc_us-gaap_VariableInterestEntityFinancialOrOtherSupportAmount_63BFBAB95F9B745E6DEC95E619F5B074" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_AdministrativeServicesRevenue" xlink:label="loc_us-gaap_AdministrativeServicesRevenue_D301B84787ABAC5BF84895E619F55702" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_C9DBF74C5B004F881B5B95E619F5AC88" xlink:to="loc_us-gaap_AdministrativeServicesRevenue_D301B84787ABAC5BF84895E619F55702" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntityConsolidatedCarryingAmountAssets" xlink:label="loc_us-gaap_VariableInterestEntityConsolidatedCarryingAmountAssets_615B1E9C2C446334C6DF95E619F5A945" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_C9DBF74C5B004F881B5B95E619F5AC88" xlink:to="loc_us-gaap_VariableInterestEntityConsolidatedCarryingAmountAssets_615B1E9C2C446334C6DF95E619F5A945" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2017/elts/us-gaap-2017-01-31.xsd#us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities" xlink:label="loc_us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities_37B3D5C9A6ED96B0041D95E619F537B9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_C9DBF74C5B004F881B5B95E619F5AC88" xlink:to="loc_us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities_37B3D5C9A6ED96B0041D95E619F537B9" xlink:type="arc" />
  </link:definitionLink>
</link:linkbase>
