POWER OF ATTORNEY

      Know all by these presents that the undersigned hereby constitutes and
appoints Janet L. Hennessy, his true attorney-in-fact to:

      (1)   execute for and on behalf of the undersigned, Rule 144 filings,
            Forms 3, 4, and 5; related to Aspen Technologies, Inc. in accordance
            with Section 16(a) of the Securities Exchange Act of 1934 and the
            rules thereunder;

      (2)   do and perform any and all acts for and on behalf of the undersigned
            which may be necessary or desirable to complete the execution of any
            such Rule 144 filings, Forms 3, 4, and 5 and the timely filing of
            such forms with the United States Securities and Exchange Commission
            and any other authority; and

      (3)   take any other action of any type whatsoever in connection with the
            foregoing which, in the opinion of such attorney-in-fact, may be of
            benefit to, in the best interest of, or legally required by, the
            undersigned, it being understood that any document filed pursuant to
            this Power of Attorney shall be in such form and shall contain such
            terms and conditions as such attorney-in-fact may approve in his/her
            discretion.

      The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform all and every act and thing whatsoever requisite,
necessary and proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or his/her
substitute or substitutes, shall lawfully do or cause to be done by virtue of
this Power of Attorney and the rights and powers granted. The undersigned
acknowledges that the foregoing attorneys-in-fact, in serving in such capacity
at the request of the undersigned, are not assuming any of the undersigned's
responsibilities to comply with any section of either the Securities Act of 1933
or the Securities Exchange Act of 1934.

      IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 11th day of August 2003.

                                            /s/ Douglas A. Kingsley
                                            ____________________________________
                                            Douglas A. Kingsley