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  <xsd:element abstract="true" id="algn_IcaHoldingsPtyLimitedMember" name="IcaHoldingsPtyLimitedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_IncomeTaxIncentivePeriod" name="IncomeTaxIncentivePeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_IncomeTaxesLineItems" name="IncomeTaxesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_IncomeTaxesTable" name="IncomeTaxesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_InvisalignExpressliteMember" name="InvisalignExpressliteMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_InvisalignFullMember" name="InvisalignFullMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_InvisalignNonCaseRevenuesMember" name="InvisalignNonCaseRevenuesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_IsraeliSeveranceFundsMember" name="IsraeliSeveranceFundsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_LapseInStatuteOfLimitationsMember" name="LapseInStatuteOfLimitationsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_LeaseTerm" name="LeaseTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_LongTermInvestmentsMember" name="LongTermInvestmentsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_MarketPerformanceBasedRestrictedStockUnitsMember" name="MarketPerformanceBasedRestrictedStockUnitsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_MarketableSecuritiesAndFairValueMeasurementsAbstract" name="MarketableSecuritiesAndFairValueMeasurementsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_MarketableSecuritiesWeightedAverageRemainingMaturity" name="MarketableSecuritiesWeightedAverageRemainingMaturity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_MaturityPeriodUsedToClassifyInvestments" name="MaturityPeriodUsedToClassifyInvestments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_MedicalDeviceExciseTaxExpenseBenefit" name="MedicalDeviceExciseTaxExpenseBenefit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="algn_MedicalDeviceExciseTaxPolicyPolicyTextBlock" name="MedicalDeviceExciseTaxPolicyPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_MergerConsideration" name="MergerConsideration" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="algn_MinimumUnrestrictedCashBalanceToBeMaintained" name="MinimumUnrestrictedCashBalanceToBeMaintained" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_MonthlyVestingMember" name="MonthlyVestingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_MunicipalSecuritiesMember" name="MunicipalSecuritiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_NationalCorporateTaxRate" name="NationalCorporateTaxRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_NoncurrentAssetsMember" name="NoncurrentAssetsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_NotesToFinancialStatementsAbstract" name="NotesToFinancialStatementsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_October2011StockRepurchaseProgramMember" name="October2011StockRepurchaseProgramMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_OtherInternationalMember" name="OtherInternationalMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_OutOfPeriodCorrectionMember" name="OutOfPeriodCorrectionMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_PercentageOfMarketPerformanceBasedRestrictedStockUnitsDuringVestingPeriod" name="PercentageOfMarketPerformanceBasedRestrictedStockUnitsDuringVestingPeriod" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ScannersAndCadcamMember" name="ScannersAndCadcamMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ScannersMember" name="ScannersMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ScheduleOfBusinessAcquisitionsPurchasePriceAllocationLineItems" name="ScheduleOfBusinessAcquisitionsPurchasePriceAllocationLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ScheduleOfBusinessAcquisitionsPurchasePriceAllocationTable" name="ScheduleOfBusinessAcquisitionsPurchasePriceAllocationTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAxis" name="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitsInPeriodWeightedAverageGrantDateFairValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitsInPeriodWeightedAverageGrantDateFairValue" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedTotalIntrinsicValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedTotalIntrinsicValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="algn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndReleasedTotalIntrinsicValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndReleasedTotalIntrinsicValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="algn_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsMethodUsedTableTextBlock" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsMethodUsedTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAggregateIntrinsicValueAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationTerm" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePricePercentageOfFairMarketValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePricePercentageOfFairMarketValue" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingPercentage" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ShareBasedCompensationArrangementsByShareBasedPaymentAwardDomain" name="ShareBasedCompensationArrangementsByShareBasedPaymentAwardDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_ShareBasedCompensationByShareBasedPaymentAwardWeightedAveragePurchasePriceOfCommonStock" name="ShareBasedCompensationByShareBasedPaymentAwardWeightedAveragePurchasePriceOfCommonStock" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_ShareRepurchaseProgramDisclosureTextBlock" name="ShareRepurchaseProgramDisclosureTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ShareRepurchasesLineItems" name="ShareRepurchasesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_ShareRepurchasesPricePaidPerShare" name="ShareRepurchasesPricePaidPerShare" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_ShareRepurchasesTable" name="ShareRepurchasesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndReleasedInPeriodWeightedAverageGrantDateFairValue" name="SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndReleasedInPeriodWeightedAverageGrantDateFairValue" nillable="true" substitutionGroup="xbrli:item" type="num:perShareItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesCountedAgainstAuthorizedMaximumPerShare" name="SharebasedCompensationArrangementBySharebasedPaymentAwardSharesCountedAgainstAuthorizedMaximumPerShare" nillable="true" substitutionGroup="xbrli:item" type="xbrli:pureItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_SignificantAccountingPoliciesLineItems" name="SignificantAccountingPoliciesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_SignificantAccountingPoliciesTable" name="SignificantAccountingPoliciesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_StandardProductWarrantyTimePeriod" name="StandardProductWarrantyTimePeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_StockIncentivePlan2005Member" name="StockIncentivePlan2005Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_StockPlan2001Member" name="StockPlan2001Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_StockRepurchaseProgramAdditionalAmountAuthorized" name="StockRepurchaseProgramAdditionalAmountAuthorized" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="algn_StockRepurchaseProgramAuthorizedAmountforNextTwelveMonths" name="StockRepurchaseProgramAuthorizedAmountforNextTwelveMonths" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_StockholderRightsPlanMember" name="StockholderRightsPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_StockholdersEquityNoteLineItems" name="StockholdersEquityNoteLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_StockholdersEquityNoteTable" name="StockholdersEquityNoteTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_TaxBenefitExpensefromStockOptionsExercisedandUtilizationofNetOperatingLossesduetoStockOptions" name="TaxBenefitExpensefromStockOptionsExercisedandUtilizationofNetOperatingLossesduetoStockOptions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="algn_TaxBenefitsShortfallsFromStockBasedAwards" name="TaxBenefitsShortfallsFromStockBasedAwards" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="algn_TaxWithholdingRelatedToVestingOfRestrictedStockUnits" name="TaxWithholdingRelatedToVestingOfRestrictedStockUnits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="algn_TreatmentPlansNumberOfOptionalReplacements" name="TreatmentPlansNumberOfOptionalReplacements" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_TreatmentPlansPeriodForAdditionalReplacementsForNoCharge" name="TreatmentPlansPeriodForAdditionalReplacementsForNoCharge" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_U.S.GovernmentTreasuryBondsMember" name="U.S.GovernmentTreasuryBondsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="algn_USGovernmentAgencyBondsMember" name="USGovernmentAgencyBondsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="algn_ValuationAllowancesAndReservesChargedToCostAndExpenseOrRevenue" name="ValuationAllowancesAndReservesChargedToCostAndExpenseOrRevenue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
</xsd:schema>





