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  <xs:element id="aciw_VariableRateOptionsAxis" abstract="true" name="VariableRateOptionsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="aciw_VariableRateOptionsDomain" abstract="true" name="VariableRateOptionsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_VariableRateOptionOneMember" abstract="true" name="VariableRateOptionOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_VariableRateOptionTwoMember" abstract="true" name="VariableRateOptionTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_ParentCompanyAndDomesticSubsidiariesMember" abstract="true" name="ParentCompanyAndDomesticSubsidiariesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_ForeignSubsidiariesMember" abstract="true" name="ForeignSubsidiariesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_PercentageOfCapitalStockPledgedAsCollateral" abstract="false" name="PercentageOfCapitalStockPledgedAsCollateral" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="aciw_DebtInstrumentConsolidatedTotalNetLeverageRatio" abstract="false" name="DebtInstrumentConsolidatedTotalNetLeverageRatio" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="aciw_DebtInstrumentConsolidatedSeniorSecuredNetLeverageRatio" abstract="false" name="DebtInstrumentConsolidatedSeniorSecuredNetLeverageRatio" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="aciw_DebtInstrumentConsolidatedInterestCoverageRatio" abstract="false" name="DebtInstrumentConsolidatedInterestCoverageRatio" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="aciw_DebtInstrumentNumberOfLetterOfCreditAgreements" abstract="false" name="DebtInstrumentNumberOfLetterOfCreditAgreements" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="aciw_DebtInstrumentIssuePricePercentageOfPrincipalAmount" abstract="false" name="DebtInstrumentIssuePricePercentageOfPrincipalAmount" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="aciw_OtherFiniteLivedIntangibleAssetsMember" abstract="true" name="OtherFiniteLivedIntangibleAssetsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_EmployeeStockPurchasePlanTwentySeventeenMember" abstract="true" name="EmployeeStockPurchasePlanTwentySeventeenMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_EquityAndIncentiveCompensationPlan2020Member" abstract="true" name="EquityAndIncentiveCompensationPlan2020Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_TwoThousandSixteenEquityandPerformanceIncentivePlanMember" abstract="true" name="TwoThousandSixteenEquityandPerformanceIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_TwoThousandFiveEquityandPerformanceIncentivePlanMember" abstract="true" name="TwoThousandFiveEquityandPerformanceIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSalaryDollars" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSalaryDollars" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementByShareBasedPaymentAwardParticipationPeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardParticipationPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="aciw_SharebasedCompensationArrangementbySharebasedPaymentAwardOptionsTerm" abstract="false" name="SharebasedCompensationArrangementbySharebasedPaymentAwardOptionsTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementsByShareBasedPaymentAwardTotalShareholderReturnMultiplier" abstract="false" name="ShareBasedCompensationArrangementsByShareBasedPaymentAwardTotalShareholderReturnMultiplier" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementsbyShareBasedPaymentAwardPerformanceSharesMaximumTarget" abstract="false" name="ShareBasedCompensationArrangementsbyShareBasedPaymentAwardPerformanceSharesMaximumTarget" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementsbyShareBasedPaymentAwardPerformanceSharesMinimumTarget" abstract="false" name="ShareBasedCompensationArrangementsbyShareBasedPaymentAwardPerformanceSharesMinimumTarget" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsIssuedInPeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsIssuedInPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsChangeInAttainment" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsChangeInAttainment" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="aciw_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsChangeInAttainmentWeightedAverageGrantDateFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsChangeInAttainmentWeightedAverageGrantDateFairValue" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:perShareItemType"/>
  <xs:element id="aciw_TreasuryStockSharesAcquiredToDate" abstract="false" name="TreasuryStockSharesAcquiredToDate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="aciw_TreasuryStockValueAcquiredCostMethodToDate" abstract="false" name="TreasuryStockValueAcquiredCostMethodToDate" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_TotalShareholderReturnAwardsTSRsMember" abstract="true" name="TotalShareholderReturnAwardsTSRsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_InterchangeCosts" abstract="false" name="InterchangeCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_GlobalTechnologyAndInnovationCosts" abstract="false" name="GlobalTechnologyAndInnovationCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_SegmentAdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" abstract="false" name="SegmentAdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_CorporateAndUnallocatedIncomeExpense" abstract="false" name="CorporateAndUnallocatedIncomeExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_BillPaymentsMember" abstract="true" name="BillPaymentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_MerchantPaymentsMember" abstract="true" name="MerchantPaymentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_FraudManagementMember" abstract="true" name="FraudManagementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_RealTimePaymentsMember" abstract="true" name="RealTimePaymentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_IssuingAndAcquiringMember" abstract="true" name="IssuingAndAcquiringMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_DigitalBusinessBankingMember" abstract="true" name="DigitalBusinessBankingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_SoftwareAndPlatformServiceMember" abstract="true" name="SoftwareAndPlatformServiceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_EffectiveIncomeTaxRateReconciliationTaxEffectOfForeignOperations" abstract="false" name="EffectiveIncomeTaxRateReconciliationTaxEffectOfForeignOperations" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_DeferredTaxAssetsOperatingLeaseLiabilities" abstract="false" name="DeferredTaxAssetsOperatingLeaseLiabilities" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_DeferredTaxLiabilitiesOperatingLeaseRightOfUseAsset" abstract="false" name="DeferredTaxLiabilitiesOperatingLeaseRightOfUseAsset" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_DeferredTaxLiabilitiesWithholdingTaxLiability" abstract="false" name="DeferredTaxLiabilitiesWithholdingTaxLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_IncomeTaxesTable" abstract="true" name="IncomeTaxesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="aciw_OtherForeignJurisdictionMember" abstract="true" name="OtherForeignJurisdictionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_NonUSExcludingIndiaMember" abstract="true" name="NonUSExcludingIndiaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_IncomeTaxesLineItems" abstract="true" name="IncomeTaxesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_OperatingLossCarryforwardsAbstract" abstract="true" name="OperatingLossCarryforwardsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_OperatingLossCarryforwardsExpirationPeriod" abstract="false" name="OperatingLossCarryforwardsExpirationPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="aciw_TaxCreditCarryforwardAbstract" abstract="true" name="TaxCreditCarryforwardAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_TaxCreditCarryforwardNotSubjecttoExpiration" abstract="false" name="TaxCreditCarryforwardNotSubjecttoExpiration" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_TaxCreditCarryforwardExpirationPeriod" abstract="false" name="TaxCreditCarryforwardExpirationPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="aciw_UnrecognizedTaxBenefitsIncreaseDecreaseResultingFromCurrencyTranslation" abstract="false" name="UnrecognizedTaxBenefitsIncreaseDecreaseResultingFromCurrencyTranslation" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_LesseeOperatingLeaseOptionToTerminate1" abstract="false" name="LesseeOperatingLeaseOptionToTerminate1" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="aciw_LesseeOperatingLeaseMonthlyBaseRent" abstract="false" name="LesseeOperatingLeaseMonthlyBaseRent" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_CashPaidForAmountsIncludedInTheMeasurementOfLeaseLiabilitiesAbstract" abstract="true" name="CashPaidForAmountsIncludedInTheMeasurementOfLeaseLiabilitiesAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_RightOfUseAssetsObtainedInExchangeForNewLeaseObligationsAbstract" abstract="true" name="RightOfUseAssetsObtainedInExchangeForNewLeaseObligationsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_OperatingLeaseNonCashAbstract" abstract="true" name="OperatingLeaseNonCashAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_OperatingLeaseSubleasePaymentsNonCash" abstract="false" name="OperatingLeaseSubleasePaymentsNonCash" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_OperatingLeaseAssetsAbstract" abstract="true" name="OperatingLeaseAssetsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_ACHFileTransmissionMember" abstract="true" name="ACHFileTransmissionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="aciw_ScheduleOfDefinedContributionPlansDisclosuresTable" abstract="true" name="ScheduleOfDefinedContributionPlansDisclosuresTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="aciw_RetirementPlanSpecificationsAxis" abstract="true" name="RetirementPlanSpecificationsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="aciw_RetirementPlanSpecificationsDomain" abstract="true" name="RetirementPlanSpecificationsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_EmployeesUnderAgeFiftyMember" abstract="true" name="EmployeesUnderAgeFiftyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_EmployeesTurningAgeFiftyOrMoreMember" abstract="true" name="EmployeesTurningAgeFiftyOrMoreMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_SecondEligibleParticipantContributionsMember" abstract="true" name="SecondEligibleParticipantContributionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_EmployeeHiredPriorToDecemberOneTwoThousandMember" abstract="true" name="EmployeeHiredPriorToDecemberOneTwoThousandMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_EmployeeHiredAfterDecemberOneTwoThousandMember" abstract="true" name="EmployeeHiredAfterDecemberOneTwoThousandMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="aciw_ScheduleOfDefinedContributionPlansDisclosuresLineItems" abstract="true" name="ScheduleOfDefinedContributionPlansDisclosuresLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="aciw_DefinedContributionPlanEmployerMatchingContributionMaximumAmountPerEmployee" abstract="false" name="DefinedContributionPlanEmployerMatchingContributionMaximumAmountPerEmployee" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="aciw_DefinedContributionPlanEmployerMatchingContributionServicePeriodRequirementForCompanyMatch" abstract="false" name="DefinedContributionPlanEmployerMatchingContributionServicePeriodRequirementForCompanyMatch" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="aciw_DefinedContributionPlanEmployerDiscretionaryContributionPercentage" abstract="false" name="DefinedContributionPlanEmployerDiscretionaryContributionPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
</xs:schema>
