-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 UxkgToyywbxWBnD6sBfwtMWlNDUK/jDLuliwGVhB16yH2MHeuBTGccwnDgtpNokX
 rO6oRXczV8yF6nwBQjdnzQ==

<SEC-DOCUMENT>0001179110-03-005996.txt : 20030820
<SEC-HEADER>0001179110-03-005996.hdr.sgml : 20030820
<ACCEPTANCE-DATETIME>20030820153306
ACCESSION NUMBER:		0001179110-03-005996
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030818
FILED AS OF DATE:		20030820

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MCQUILLIN DAVID L
		CENTRAL INDEX KEY:			0001251379

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-24786
		FILM NUMBER:		03858086

	BUSINESS ADDRESS:	
		STREET 1:		ASPEN TECHNOLOGY INC
		STREET 2:		TEN CANAL PARK
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
		BUSINESS PHONE:		6179491000

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ASPEN TECHNOLOGY INC /DE/
		CENTRAL INDEX KEY:			0000929940
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER PROGRAMMING SERVICES [7371]
		IRS NUMBER:				042739697
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		TEN CANAL PARK
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
		BUSINESS PHONE:		6179491000

	MAIL ADDRESS:	
		STREET 1:		TEN CANAL PARK
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-08-18</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000929940</issuerCik>
        <issuerName>ASPEN TECHNOLOGY INC /DE/</issuerName>
        <issuerTradingSymbol>AZPN</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251379</rptOwnerCik>
            <rptOwnerName>MCQUILLIN DAVID L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ASPEN TECHNOLOGY, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>10 CANAL PARK</rptOwnerStreet2>
            <rptOwnerCity>CAMBRIDGE</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02141</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>President and CEO</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable></nonDerivativeTable>
<derivativeTable><derivativeTransaction><securityTitle><value>Option to purchase common stock</value>
</securityTitle>
<conversionOrExercisePrice><value>2.75</value>
</conversionOrExercisePrice>
<transactionDate><value>2003-08-18</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>A</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>1516609</value>
</transactionShares>
<transactionPricePerShare><value>2.75</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate><footnoteId id="F1"></footnoteId>
</exerciseDate>
<expirationDate><value>2013-08-18</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>common stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>1516609</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>1516609</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeTransaction>
</derivativeTable>
<footnotes><footnote id="F1">Option vests in 16 equal quarterly installments beginning on September 30, 2003.</footnote>
</footnotes>
<ownerSignature><signatureName>/s/ David L. McQuillin</signatureName>
<signatureDate>2003-08-20</signatureDate>
</ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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