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                                                           Registration No. 333-



                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549


                                    FORM S-8

                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933

                             Aspen Technology, Inc.
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             (Exact Name of Registrant as Specified in Its Charter)

                                    Delaware
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         (State or Other Jurisdiction of Incorporation or Organization)

                                   04-2739697
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                      (I.R.S. Employer Identification No.)

                 Ten Canal Park, Cambridge, Massachusetts 02141
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               (Address of Principal Executive Offices) (Zip Code)

              Aspen Technology, Inc. 1996 Special Stock Option Plan
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                            (Full Title of the Plan)

                                Lawrence B. Evans
                             Aspen Technology, Inc.
                                 Ten Canal Park
                         Cambridge, Massachusetts 02141
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                     (Name and Address of Agent for Service)

                                 (617) 577-0100
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          (Telephone Number, Including Area Code, of Agent For Service)

                                 With copies to:
     Stephen J. Doyle, Esq.                       Mark L. Johnson, Esq.
Vice President and General Counsel               Foley, Hoag & Eliot LLP
     Aspen Technology, Inc.                      One Post Office Square
        Ten Canal Park                         Boston, Massachusetts 02109
 Cambridge, Massachusetts 02141



                             CALCULATION OF REGISTRATION FEE
=============================================================================================

                                               
Proposed Title of Proposed Maximum Securities Amount Maximum Aggregate Amount of to be to be Offering Price Offering Registration Registered Registered Per Share(1) Price(1) Fee - -------------------------------------------------------------------------------------------- Common Stock, $.10 par value 250,000 shares $66.875(2) $16,718,750 $5,067 ============================================================================================ (1) Estimated solely for the purpose of determining the registration fee. (2) In accordance with Rules 457(c) and (h) under the Securities Act of 1933, the above calculation is based on the average of the high and low sale prices reported in the consolidated reporting system of the Nasdaq National Market on February 5, 1997.
2 PART II INFORMATION REQUIRED IN THE REGISTRATION STATEMENT ITEM 3. INCORPORATION OF DOCUMENTS BY REFERENCE. The following documents heretofore filed by Aspen Technology, Inc. (the "Registrant") with the Securities and Exchange Commission (the "Commission") pursuant to the Securities Exchange Act of 1934, as amended (the "Exchange Act"), are incorporated by reference in this Registration Statement: (1) the Registrant's Annual Report on Form 10-K for the fiscal year ended June 30, 1996 (the "Annual Report"); (2) the Registrant's definitive Proxy Statement dated November 11, 1996 used in connection with its Annual Meeting of Stockholders held on December 16, 1996; (3) the Registrant's Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 1996; (4) the Registrant's Current Report on Form 8-K dated January 29, 1997; and (5) the description of the Common Stock contained in the Registrant's registration statement filed with the SEC under Section 12(g) of the Exchange Act, including any amendment or report filed for the purpose of updating such description. In addition, all reports and other documents subsequently filed by the Registrant pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this Prospectus and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregister all of such securities then remaining unsold, shall be deemed to be incorporated by reference into this Registration Statement and to be a part hereof from the date of filing of such documents. ITEM 4. DESCRIPTION OF SECURITIES Not applicable. ITEM 5. INTERESTS OF NAMED EXPERTS OR COUNSEL Not applicable. ITEM 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS Article 6 of the Company's Restated Articles of Organization provides that the Company shall indemnify each person who is or was a director, officer, employee or other agent of the Company, and each person who is or was serving at the request of the Company as a director, trustee, officer, employee or other agent of another organization in which it directly or indirectly owns shares or of which it is directly or indirectly a creditor, against all liabilities, costs and expenses reasonably incurred by any such persons in connection with the defense or disposition of or otherwise in connection with or resulting from any action, suit, or other proceeding in which they may be involved by reason of being or having been such a director, officer, employee agent or trustee, or by reason of any action taken or not taken in such capacity, except with respect to any matter as to which such person shall have been finally adjudicated by a court of competent jurisdiction not to have acted in good faith in the reasonable belief that his or her action was in the best interests of the Company. The provisions of the Company's Articles pertaining to indemnification may not be amended and no provision inconsistent therewith may be adopted without the approval of either the Board of Directors or the holders of at least a majority of the voting power of the Company. These provisions do not eliminate a director's duty of care. Moreover, the provisions do not apply to claims against a director for violations of certain laws, including federal securities laws. Section 67 of Chapter 156B of the Massachusetts Business II-1 3 Corporation Law authorizes a corporation to indemnify its directors, officers, employees and other agents unless such person shall have been adjudicated in any proceeding not to have acted in good faith in the reasonable belief that such action was in the best interests of the corporation. The Company maintains a directors' and officers' insurance policy that covers certain liabilities of directors and officers of the Company, including liabilities under the Securities Act of 1933. The Company maintains a general liability insurance policy that covers certain liabilities of directors and officers of the Company arising out of claims based on acts or omissions in their capacities as directors or officers. ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED Not applicable. ITEM 8. EXHIBITS EXHIBIT NUMBER 4.1(a)* Restated Articles of Organization of the Registrant, as filed with the Secretary State of the Commonwealth of Massachusetts on November 1, 1994 4.1(b) Articles of Amendment to the Restated Articles of Organization of the Registrant, as filed with the Secretary of State of the Commonwealth of Massachusetts on January 6, 1997 4.2* By-Laws of the Registrant 4.3* Specimen certificate for the Common Stock 4.4 Aspen Technology, Inc. 1996 Special Stock Option Plan 5.1 Opinion of Foley, Hoag & Eliot LLP 23.1 Consent of Arthur Andersen LLP 23.2 Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1) 24 Power of Attorney (included on pages II-4 and II-5) - ---------- * Filed as an exhibit to the Company's Registration Statement on Form S-1 (registration number 33-88734), as filed with the Commission on January 29, 1995, and incorporated herein by reference. ITEM 9. UNDERTAKINGS 1. The undersigned Registrant hereby undertakes: (a) To file, during any period in which offers or sales are being made, a post-effective amendment to this Registration Statement: II-2 4 (i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933; (ii) To reflect in the prospectus any facts or events arising after the effective date of the Registration Statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the Registration Statement; (iii) To include any material information with respect to the plan of distribution not previously disclosed in the Registration Statement or any material change to such information in the Registration Statement; PROVIDED, HOWEVER, that paragraphs 2 (a)(1)(i) and 2 (a)(1)(ii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed by the Registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference herein. (b) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial BONA FIDE offering thereof. (c) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering. 2. The undersigned Registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the Registration Statement shall be deemed to be a new registration statement relating to the securities offered herein, and the offering of such securities at that time shall be deemed to be the initial BONA FIDE offering thereof. 3. Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the Registrant pursuant to the foregoing provisions, or otherwise, the Registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue. II-3 5 SIGNATURES Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cambridge, Massachusetts, on this tenth day of February, 1997. ASPEN TECHNOLOGY, INC. /s/ LAWRENCE B. EVANS By:------------------------------------------------- Lawrence B. Evans Chairman of the Board and Chief Executive Officer POWER OF ATTORNEY KNOW ALL MEN BY THESE PRESENTS that each individual whose signature appears below constitutes and appoints Lawrence B. Evans, Mary A. Palermo, Joel B. Rosen and Lisa W. Zappala, and each of them, true and lawful attorneys-in-fact and agents with full power of substitution, for and in name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to file the same, with all exhibits thereto, and all documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing which they, or any of them, may deem necessary or advisable to be done in connection with this Registration Statement, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or any substitute or substitutes for any or all of them, may lawfully do or cause to be done by virtue hereof. Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the indicated capacities as of February 10, 1997. SIGNATURE TITLE /s/ LAWRENCE B. EVANS - ------------------------------- Chairman of the Board and Lawrence B. Evans Chief Executive Officer (Principal Executive Officer) /s/ MARY A. PALERMO - ------------------------------- Executive Vice President, Finance and Chief Mary A. Palermo Financial Officer (Principal Financial and Accounting Officer) /s/ JOSEPH F. BOSTON - ------------------------------- Director Joseph F. Boston - ------------------------------- Director Gresham T. Brebach, Jr. II-4 6 /s/ DOUGLAS R. BROWN - ------------------------------- Director Douglas R. Brown - ------------------------------- Director Joan C. McArdle /s/ ALISON ROSS - ------------------------------- Director Alison Ross II-5 7 INDEX TO EXHIBITS EXHIBIT NUMBER DESCRIPTION 4.1(a)* Restated Articles of Organization of the Registrant, as filed with the Secretary State of the Commonwealth of Massachusetts on November 1, 1994 4.1(b) Articles of Amendment to the Restated Articles of Organization of the Registrant, as filed with the Secretary of State of the Commonwealth of Massachusetts on January 6, 1997 4.2* By-Laws of the Registrant 4.3* Specimen certificate for the Common Stock 4.4 Aspen Technology, Inc. 1996 Special Stock Option Plan 5.1 Opinion of Foley, Hoag & Eliot LLP 23.1 Consent of Arthur Andersen LLP 23.2 Consent of Foley, Hoag & Eliot LLP (included in Exhibit 5.1) 24 Power of Attorney (included on pages II-4 and II-5) - ---------- * Filed as an exhibit to the Company's Registration Statement on Form S-1 (registration number 33-88734), as filed with the Commission on January 29, 1995, and incorporated herein by reference. II-6
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                        THE COMMONWEALTH OF MASSACHUSETTS
                             WILLIAM FRANCIS GALVIN
                          Secretary of the Commonwealth
              One Ashburton Place, Boston, Massachusetts 02108-1512

                              ARTICLES OF AMENDMENT
                    (GENERAL LAWS, CHAPTER 156B, SECTION 72)

We, Joseph F. Boston, President, and Stephen J. Doyle, Assistant Clerk, of Aspen
Technology, Inc., located at: Ten Canal Park, Cambridge, MA 02141, certify that
these Articles of Amendment affecting articles numbered: Article 3 and Article 4
of the Articles of Organization were duly adopted at a meeting held on December
16, 1996, by vote of: 5,241,622 shares of Common of 9,729,730 shares
outstanding, being at least a majority of each type, class or series outstanding
and entitled to vote thereon.

That Section 3 of the Corporation's Articles of Organization is hereby amended
to read in its entirety as follows:

3.    The total number of shares and the par value, if any, of each class of
      capital stock which the corporation is authorized to issue as follows:

                        WITHOUT PAR VALUE              WITH PAR VALUE
      CLASS OF STOCK    NUMBER OF SHARES      NUMBER OF SHARES     PAR VALUE
      Preferred                               10,000,000           $0.10
      Common                                  40,000,000           $0.10

That Section 4 of the Corporation's Articles of Organization is hereby amended
to read in its entirety as follows:

4.    If more than one class is authorized, a description of each of the
      different classes of stock, with, if any, the preferences, voting powers,
      qualifications, special or relative rights or privileges as to each class
      thereof and any series now established:

      The Corporation shall have authority to issue 50,000,000 shares of capital
      stock of which 40,000,000 shares shall be Common Stock in the amount as
      set forth below and 10,000,000 shares shall be preferred stock in the
      amount set forth below:

      CLASSIFICATION               NO. OF SHARES                 PAR VALUE
      Common Stock                   40,000,000                    $0.10
      Preferred Stock                10,000,000                    $0.10

      The shares of preferred stock may be issued from time to time in one or
      more classes or series. The Board of Directors is hereby authorized to
      establish and designate the different class or series, and to fix and
      determine preferences, voting powers, qualifications, and special or
      relative rights or privileges thereof and such designations as shall be
      stated in a vote or votes providing for the issue of such class or series
      adopted by the Board of Directors, which preferences, voting powers,
      qualifications, and special or relative rights or privileges need not be
      uniform among class or series. Any of the preferences, voting powers,
      qualifications, and special or relative rights or privileges of any such
      class or series of stock may be made dependent upon facts ascertainable
      outside the vote or votes providing for the issue of such stock


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      adopted by the Board of Directors, provided that the manner in which such
      facts shall operate upon the preferences, voting powers, qualifications,
      and special or relative rights or privileges of such class or series of
      stock is clearly and expressly set forth in the vote or votes providing
      for the issue of such class or series adopted by the Board of Directors.
      Prior to the issuance of any shares of the class or series having terms so
      determined by the Board of Directors other than a reissue of shares as
      shares of the same class and series, the Corporation shall submit to the
      Secretary of State a certificate signed by the President or a Vice
      President and by the Clerk or an Assistant Clerk setting forth the text of
      the vote or votes of the Board of Directors determining the terms of the
      class or series or the number of votes and a certificate that such vote or
      votes were duly adopted by the Board of Directors.

To change the number of shares and the par value (if any) of any type, class or
series of stock which the corporation is authorized to issue, fill in the
following:

The total PRESENTLY authorized is:

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       WITHOUT PAR VALUE STOCKS                 WITH PAR VALUE STOCKS
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TYPE      NUMBER OF SHARES            TYPE        NUMBER OF SHARES     PAR VALUE
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Common:                               Common:     15,000,000           .10
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- --------------------------------------------------------------------------------
Preferred:                            Preferred:  10,000,000           .10
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CHANGE the total authorized to:

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       WITHOUT PAR VALUE STOCKS                 WITH PAR VALUE STOCKS
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TYPE      NUMBER OF SHARES            TYPE        NUMBER OF SHARES     PAR VALUE
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Common:                               Common:     40,000,000           .10
- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------
Preferred:                            Preferred:  10,000,000           .10
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- --------------------------------------------------------------------------------

The foregoing amendment(s) will become effective when these Articles of
Amendment are filed in accordance with General Laws, Chapter 156B, Section 6
unless these articles specify, in accordance with the vote adopting the
amendment, a LATER effective date not more than THIRTY DAYS after such filing,
in which event the amendment will become effective on such later date.

Later effective date: _________________

SIGNED UNDER THE PENALTIES OF PERJURY, this 6th day of January, 1997.
/s/ JOSEPH F. BOSTON, President
/s/ STEPHEN J. DOYLE, Assistant Clerk


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                        THE COMMONWEALTH OF MASSACHUSETTS

                              ARTICLES OF AMENDMENT
                    (General Laws, Chapter 156B, Section 72)


================================================================================


I hereby approve the within Articles of Amendment, and the filing fee in the
amount of $25,100 having been paid, said article is deemed to have been filed
with me this 6th day of January, 1997.




EFFECTIVE DATE:
               -----------------------------------------------------------------









                           /s/ WILLIAM FRANCIS GALVIN
                             WILLIAM FRANCIS GALVIN
                          SECRETARY OF THE COMMONWEALTH










                         TO BE FILLED IN BY CORPORATION
                      Photocopy of document to be sent to:

                             Aspen Technology, Inc.
                                 Ten Canal Park
                               Cambridge, MA 02141
                              Attn: Karen Hrynyszyn




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                             ASPEN TECHNOLOGY, INC.

                         1996 SPECIAL STOCK OPTION PLAN


          1. DEFINITIONS. As used in this 1996 Special Stock Option Plan of
Aspen Technology, Inc., the following terms shall have the following meanings:

               1.1. CHANGE IN CORPORATE CONTROL means the date on which any
individual, corporation, partnership or other person or entity (together with
its "Affiliates" and "Associates," as defined in Rule 12b-2 under the Securities
Exchange Act of 1934) "beneficially owns" (as defined in Rule 13d-3 under the
Securities Exchange Act of 1934) in the aggregate 20% or more of the outstanding
shares of capital stock of the Company entitled to vote generally in the
election of directors of the Company.

               1.2. CODE means the Internal Revenue Code of 1986, as amended.

               1.3. COMMITTEE means the Compensation Committee of the Company's
Board of Directors.

               1.4. COMPANY means Aspen Technology, Inc., a Massachusetts
corporation.

               1.5. DATE OF ACQUISITION means the closing date of an
acquisition, and if a business is acquired in more than one purchase
transaction, the last closing date to occur, provided such closings are related
transactions under a plan for the acquisition of such business by the Company.

               1.6. DIRECTOR means any person on the board of directors of an
acquired business, excluding however persons who were employed by the Company
prior to and on the date of acquisition of such business by the Company.

               1.7. EMPLOYEE means any person employed by an acquired business
prior to and on the date of acquisition of such business by the Company.

               1.8. FAIR MARKET VALUE means the value of a share of Stock of the
Company on any date as determined by the Committee.

               1.9. GRANT DATE means the date on which an Option is granted, as
specified in Section 7.

               1.10. INCENTIVE OPTION means an option which qualifies for tax
treatment under Section 422 of the Code.

               1.11. MAJOR SHAREHOLDER means a person who, within the meaning of
Section 422(b)(6) of the Code, is deemed to own stock possessing more than 10%
of the total combined voting power of all classes of stock of the Company (or of
its parent or subsidiary corporations).

               1.12. OPTION means an option to purchase shares of the Stock
granted under the Plan.


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               1.13. OPTION AGREEMENT means an agreement between the Company and
an Optionee, setting forth the terms and conditions of an Option.

               1.14. OPTION PRICE means the price paid by an Optionee for a
share of Stock under this Plan.

               1.15. OPTION SHARE means any share of Stock of the Company
transferred to an Optionee upon exercise of an Option pursuant to this Plan.

               1.16. OPTIONEE means a person eligible to receive an Option, as
provided in Section 6, to whom an Option shall have been granted under the Plan.

               1.17. PLAN means this 1996 Special Stock Option Plan of the
Company.

               1.18. RELATED CORPORATION means a Parent Corporation or a
Subsidiary Corporation, each as defined in Section 424 of the Code.

               1.19. STOCK means common stock, $.10 par value, of the Company.

          2. PURPOSE. This 1996 Special Stock Option Plan is intended to
encourage ownership of the Stock by Employees, consultants and Directors of
businesses acquired by the Company and to provide additional incentive for them
to promote the success of the Company's business. The Plan is intended to be an
incentive stock option plan within the meaning of Section 422 of the Code, but
not all the Options must be Incentive Options.

          3. TERM OF THE PLAN. Options under the Plan may be granted not later
than November 30, 2006.

          4. STOCK SUBJECT TO THE PLAN. Subject to the provisions of Section 16
of the Plan, the number of shares of the Stock attributable to the exercise of
Options granted under the Plan plus the number of shares then issuable upon
exercise of outstanding options granted under the Plan shall at no time exceed
250,000. Shares to be issued upon the exercise of Options granted under the Plan
may be either authorized but unissued shares or shares held by the Company in
its treasury. If any Option expires or terminates for any reason without having
been exercised in full, the shares not purchased thereunder shall again be
available for Options thereafter to be granted.

          5. ADMINISTRATION. The Plan shall be administered by the Committee.
Subject to the provisions of the Plan, the Committee shall have complete
authority, in its discretion, to make the following determinations with respect
to each Option to be granted by the Company: (a) the Employee or consultant or
Director of an acquired business to receive the Option; (b) the time of granting
the Option; (c) the number of shares subject thereto; (d) the Option Price; (e)
the Option period; and (f) if the Optionee is an employee after the acquisition
is effected, whether the Option is an Incentive Option. In making such
determinations, the Committee may take into account the nature of the services
rendered by the Employees and consultants and Directors, their present and
potential contributions to the success of the Company and its Related
Corporations, and such other factors as the Committee in its discretion shall
deem relevant. Subject to the provisions of the Plan, the Committee shall also
have complete authority to interpret the Plan, to prescribe, amend and rescind
rules and regulations relating to it, to determine the terms and provisions of
the respective Option Agreements (which need not be identical), and to make all
other determinations necessary or advisable for the administration of the Plan.
The Committee's determinations on the matters referred to in this Section 5
shall be conclusive.


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          6. ELIGIBILITY. An Option may be granted only to an Employee,
consultant or Director of a business acquired by the Company. A Major
Shareholder shall be eligible to receive an Incentive Option only if the Option
Price is at least 110% of the Fair Market Value on the Grant Date and only if
the Incentive Option expires, to the extent not theretofore exercised, on the
fifth anniversary of the Grant Date.

          7. TIME OF GRANTING OPTIONS. The granting of an Option shall take
place at the time specified by the Committee, but not later than six months
after the Date of Acquisition with respect to which the grant is made. Only if
expressly so provided by the Committee, shall the Grant Date be the date on
which an Option Agreement shall have been duly executed and delivered by the
Company and the Optionee.

          8. OPTION PRICE. The Option Price under each Incentive Option shall be
not less than 100% of the Fair Market Value of the Stock on the Grant Date
except that the Option Price under an Incentive Option granted to a Major
Shareholder must be not less than 110% of the Fair Market Value.

          9. OPTION PERIOD. No Option may be exercised later than the tenth
anniversary of the Grant Date or, for an Incentive Option granted to a Major
Shareholder, the fifth anniversary of the Grant Date. Unless the Committee
otherwise determines, all Options granted hereunder shall permit the Optionee to
purchase, cumulatively, one-sixteenth of the Option Shares at the end of each
calendar quarter beginning after the Grant Date. Upon a Change in Corporate
Control, each outstanding Option shall immediately become fully exercisable.

          10. MAXIMUM SIZE OF OPTION. To the extent that the aggregate Fair
Market Value of Stock for which an Incentive Option becomes exercisable by an
Optionee for the first time in any calendar year exceeds $100,000, the Option
shall be treated as a nonstatutory option, and not an Incentive Option. For
purposes of this Section 10, all Options granted to an Optionee by the Company
shall be considered in the order in which they were granted, and the Fair Market
Value shall be determined as of the Grant Dates.

          11. EXERCISE OF OPTION. An Option may be exercised only by giving
written notice, in the manner provided in Section 20 hereof, specifying the
number of shares as to which the Option is being exercised, accompanied by (a)
full payment for such shares in the form of check or bank draft payable to the
order of the Company, or (b) certificates representing shares of the Stock with
a current Fair Market Value equal to the Option Price of the shares to be
purchased, or (c) irrevocable instructions to a brokerage firm to sell a
sufficient number of the Option Shares to generate the full exercise price plus
all applicable withholding taxes and to pay over to the Company such proceeds of
sale. Receipt by the Company of such notice and payment shall constitute the
exercise of the Option or a part thereof. The Company shall thereafter deliver
or cause to be delivered to the Optionee a certificate or certificates for the
number of shares then being purchased by the Optionee. Such shares shall be
fully paid and nonassessable. If any law or applicable regulation of the
Securities and Exchange Commission or other body having jurisdiction in the
premises shall require the Company or the Optionee to take any action in
connection with shares being purchased upon exercise of the option, exercise of
the option and delivery of the certificate or certificates for such shares shall
be postponed until completion of the necessary action, which shall be taken at
the Company's expense.

          12. NOTICE OF DISPOSITION OF STOCK PRIOR TO EXPIRATION OF SPECIFIED
HOLDING PERIOD. The Company may require that the person exercising an Incentive
Option give a written representation to the Company, satisfactory in form and
substance to its counsel and upon which the Company may reasonably rely, that he
or she will report to the Company any disposition of shares
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purchased upon exercise prior to the expiration of the holding periods
specified by Section 422(a)(1) of the Code. If and to the extent that the
disposition imposes upon the Company federal, state, local or other withholding
tax requirements, or any such withholding is required to secure for the Company
an otherwise available tax deduction, the Company shall have the right to
require that the person making the disposition remit to the Company an amount
sufficient to satisfy those requirements.

          13. TRANSFERABILITY OF OPTIONS. Options shall not be transferable,
otherwise than by will or the laws of descent and distribution, and may be
exercised during the life of the Optionee only by the Optionee.

          14. STOCK PURCHASE AGREEMENT. Each Optionee exercising an option, at
the request of the Company, will be required to sign a Stock Purchase Agreement
representing in form satisfactory to counsel for the Company that he or she will
not transfer, sell or otherwise dispose of the Option Shares at any time
purchased by him or her, upon the exercise of any portion of the Option, in a
manner which would violate the Securities Act of 1933, as amended, and the
regulations of the Securities and Exchange Commission thereunder; and the
Company may, at its discretion, make a notation on any certificates issued upon
exercise of options to the effect that such certificate may not be transferred
except after receipt by the Company of an opinion of counsel satisfactory to it
to the effect that such transfer will not violate such Act and such regulations,
and may issue "stop transfer" instructions to its transfer agent, if any, and 
make a "stop transfer" notation on its books as appropriate. Such Stock Purchase
Agreement shall include such other provisions as the Committee may determine are
appropriate.

          15. TERMINATION OF EMPLOYMENT. In the event that the Optionee's
employment or consulting relationship is terminated for any reason other than
death or the Optionee's employer is no longer the Company or a Related
Corporation, the Option, to the extent exercisable at termination, may be
exercised by the Optionee at any time within 30 days after termination unless
terminated earlier by its terms. If termination results from the death of the
Optionee, the Option, to the extent exercisable at the date of death, may be
exercised by the person to whom the Option is transferred by will or the
applicable laws of descent and distribution, at any time within 12 months after
the date of death, unless terminated earlier by its terms. Military or sick
leave shall not be deemed a termination of employment provided that it does not
exceed the longer of 90 days or the period during which the absent employee's
re-employment rights are guaranteed by statute or by contract.

          16. ADJUSTMENT OF NUMBER OF SHARES. Each Option Agreement shall
provide that in the event of any capital adjustments including stock splits,
stock contractions, stock dividends, reclassifications, exchanges and
substitutions, occurring after the date of the option and prior to the exercise
in full of the option, the number of shares for which the option may be
exercised and the price per share shall be proportionately adjusted and in the
event of any resulting changes in the outstanding Stock, the number of shares of
the Stock available for the purpose of the Plan as stated in Section 4 hereof
shall be correspondingly adjusted.

          17. STOCK RESERVED. The Company shall at all times during the term of
the Option reserve and keep available such number of shares of the Stock as will
be sufficient to satisfy the requirements of this Plan and shall pay all fees
and expenses necessarily incurred by the Company in connection therewith.

          18. LIMITATION OF RIGHTS IN THE OPTION SHARES. An Optionee shall not
be deemed for any purpose to be a stockholder of the Company with respect to any
of the Option Shares except to the extent that the Option shall have been
exercised with respect thereto and, in addition, a certificate shall have been
issued therefor and delivered to the Optionee.              
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          19. TERMINATION AND AMENDMENT OF THE PLAN. The Board of Directors of
the Company may at any time terminate the Plan or make such amendment to the
Plan as it shall deem advisable, provided that, except as provided in Section
16, it may not, without the approval by the holders of a majority of the Stock,
change the classes of persons eligible to receive Options, increase the maximum
number of shares available for option under the Plan or extend the period during
which Options may be granted or exercised. No termination or amendment of the
Plan may, without the consent of the Optionee to whom any Option shall
theretofore have been granted, adversely affect the rights of such Optionee
under such Option. The Company may also, in its discretion, permit any option to
be exercised prior to the date on which it vests.

          20. NOTICES. Any communication or notice required or permitted to be
given under the Plan shall be in writing, and mailed by registered or certified
mail or delivered in hand, if to the Company, to its Chief Financial Officer at
Ten Canal Park, Cambridge, MA 02141 and, if to the Optionee, to the address as
the Optionee shall last have furnished to the Company.

   1
                             FOLEY, HOAG & ELIOT LLP
                             One Post Office Square
                        Boston, Massachusetts 02109-2170
                            Telephone: (617) 832-1000
                            Facsimile: (617) 832-7000
                                  Telex 940693
                               http://www.fhe.com



                                         February 11, 1997


ASPEN TECHNOLOGY, INC.
Ten Canal Park
Cambridge, Massachusetts  02141

Ladies and Gentlemen:

     We have acted as counsel for Aspen Technology, Inc., a Massachusetts
corporation (the "Company"), in connection with the preparation and filing with
the Securities and Exchange Commission under the Securities Act of 1933, as
amended, of a Registration Statement on Form S-8 (the "Registration Statement")
relating to the offering of up to 250,000 shares (the "Shares") of the Company's
common stock, $.10 par value, issuable, either under options currently issued
and outstanding or under options issuable subsequent to the date hereof,
pursuant to the Aspen Technology, Inc. 1996 Special Stock Option Plan (the
"Plan").

     In arriving at the opinions expressed below, we have examined and relied on
the following documents:

     (i)   the Registration Statement;

     (ii)  the Plan;

     (iii) the Articles of Organization of the Company, as amended as of the
           date hereof;

     (iv)  the By-Laws of the Company, as amended as of the date hereof; and

     (v)   the records of meetings and consents of the Board of Directors and
           stockholders of the Company provided to us by the Company.

In addition, we have examined and relied on the originals or copies certified or
otherwise identified to our satisfaction of all such other records, documents
and instruments of the Company and such other persons, and we have made such
investigations of law, as we have deemed appropriate as a basis for the opinions
expressed below. We have assumed the genuineness of all signatures and the
authenticity of all documents submitted to us as originals and the conformity to
the original documents of all documents submitted to us as certified or
photostatic copies.

     We express no opinion other than as to the laws of the Commonwealth of
Massachusetts.

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ASPEN TECHNOLOGY, INC.
February 11, 1997
Page Two


     Based upon the foregoing, we are of the opinion that:


     1. The Company has the corporate power necessary for the issuance of the
Shares under the Plan, as contemplated by the Registration Statement.

     2. The Shares have been duly authorized and, when issued against payment of
the agreed consideration therefor in accordance with the exercise prices
therefor as described in the respective options relating thereto and the Plan,
will be validly issued, fully paid and non-assessable.

     We consent to the filing of this opinion as Exhibit 5.1 to the Registration
Statement.

                                         Very truly yours,

                                         FOLEY, HOAG & ELIOT LLP


                                          
                                         By /s/ Mark L. Johnson
                                           -----------------------------------
                                            A Partner

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                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


     As independent public accountants, we hereby consent to the incorporation
by reference in this Registration Statement on Form S-8 of our report included
in the Annual Report on Form 10-K of Aspen Technology, Inc. for the fiscal year
ended June 30, 1996.


                                          /s/ Arthur Andersen LLP
                                         ARTHUR ANDERSEN LLP


Boston, Massachusetts
February 10, 1997