1
                             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.


   2


               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.


   3
 

          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
   4
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.              
   5
          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.