<PAGE>
 
             As filed with the Securities and Exchange Commission
                                on June 8, 1998

                                         Registration No. ______________________

--------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                       PARAMETRIC TECHNOLOGY CORPORATION
--------------------------------------------------------------------------------
            (Exact name of registrant as specified in its charter)

            Massachusetts                                     04-2866152
            -------------                                     ----------
(State or other jurisdiction of                             (I.R.S. Employer
incorporation or organization)                              Identification No.)

                   128 Technology Drive, Waltham, MA              02154
                   ---------------------------------              -----
                   (Address of Principal Executive Offices)     (Zip Code)

                      1997 NONSTATUTORY STOCK OPTION PLAN
                      -----------------------------------
                             (Full title of Plan)

                                Edwin J. Gillis
                     Executive Vice President of Finance &
                       Administration, CFO and Treasurer
                       Parametric Technology Corporation
                             128 Technology Drive
                         Waltham, Massachusetts 02154
                         ----------------------------
                    (Name and address of agent for service)

                                (781) 398-5000
                                --------------
                  (Telephone number, including area code, of
                              agent for service)


                        CALCULATION OF REGISTRATION FEE
                        -------------------------------
<TABLE>
<CAPTION>
 
                                                Proposed          Proposed
Title of securities       Amount to be      maximum offering  maximum aggregate     Amount of
to be registered           registered       price per share    offering price    registration fee
---------------------  -------------------  ----------------  -----------------  ----------------
<S>                    <C>                  <C>               <C>                <C>
 
Common Stock,          12,000,000 shares (1)       $30.375 (2)   $364,500,000 (2)     $107,527.50
$.01 par value
</TABLE>

--------------------------------------------------------------------------------
(1)  This Registration Statement registers shares to be offered by Registrant
pursuant to its 1997 Nonstatutory Stock Option Plan.

(2)  Estimated solely for the purpose of calculating the registration fee in
accordance with Rule 457(h) under the Securities Act of 1933, and based on the
average of the high and low sale prices of the Common Stock as reported by the
Nasdaq Stock Market's National Market on June 1, 1998.

                               Page 1 of 9 Pages
                            Exhibit Index on Page 5
<PAGE>
 
STATEMENT REGARDING INCORPORATION BY REFERENCE FROM EFFECTIVE REGISTRATION
STATEMENT.

  Pursuant to General Instruction E to Form S-8, the contents of the
Registration Statement on Form S-8 of Parametric Technology Corporation (the
"Company"), as filed with the Securities and Exchange Commission (the
"Commission") on June 4, 1997 (Commission File No. 333-28495) (the "Original
Registration Statement"), relating to the registration of 5,000,000 shares of
the Company's Common Stock, $.01 par value per share (the "Common Stock"),
authorized for issuance under the Company's 1997 Nonstatutory Stock Option Plan
(the "1997 Plan"), is incorporated by reference in its entirety herein.  Since
the filing of the Original Registration Statement, one Registration Statement on
Form S-8 has been filed with the Commission on October 24, 1997 (Commission File
No. 333-38629) relating to the registration of 1,200,000 additional shares of
Common Stock for issuance under the 1997 Plan.  This Registration Statement
provides for the registration of an additional 12,000,000 shares of Common Stock
authorized for issuance under the 1997 Plan.  All Common Stock share numbers in
this Form S-8 have been adjusted to reflect the one-for-one stock dividend on
all issued and outstanding shares of Common Stock (excluding shares held in the
Company's treasury) declared by the Company's Board of Directors on February 12,
1998 and effective on March 6, 1998.

                                       2
<PAGE>
 
                                   SIGNATURES
                                   ----------

  Pursuant to the requirements of the Securities Act of 1933, as amended, 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 Waltham, Massachusetts, on the 5th day of June, 1998.


                                    PARAMETRIC TECHNOLOGY CORPORATION


                                    
                                    By: /s/ Steven C. Walske
                                       ---------------------
                                       Steven C. Walske
                                       Chief Executive Officer 
                                        and Chairman of the Board


                               POWER OF ATTORNEY
                               -----------------

          We, the undersigned officers and directors of Parametric Technology
Corporation, hereby severally constitute C. Richard Harrison, Edwin J. Gillis,
Martha L. Durcan, Esq., and Mathew C. Dallett, Esq., and each of them singly,
our true and lawful attorneys with full power to them, and each of them singly,
to sign for us and in our names in the capacities indicated below, the
Registration Statement on Form S-8 filed herewith and any and all subsequent
amendments to said Registration Statement, and generally to do all such things
in our names and behalf in our capacities as officers and directors to enable
Parametric Technology Corporation to comply with all requirements of the
Securities and Exchange Commission, hereby ratifying and confirming our
signatures as they may be signed by said attorneys, or any of them, to said
registration statement and any and all amendments thereto.

          WITNESS our hands and common seal on the date set forth below.

          Pursuant to the requirements of the Securities Act of 1933, as
amended, this Registration Statement has been signed below by the following
persons in the capacities and on the dates indicated.


     Signature                           Title                        Date
     ---------                           -----                        ----

(i)  Principal Executive Officer:


      /s/ Steven C. Walske               Chief Executive           June 5, 1998
     ---------------------               Officer and Chairman 
     Steven C. Walske                    of the Board

(ii) Principal Financial and Accounting Officer:


      /s/ Edwin J. Gillis                Executive Vice            June 5, 1998
     --------------------                President of Finance 
     Edwin J. Gillis                     & Administration, 
                                         Chief Financial Officer 
                                         and Treasurer

                                       3
<PAGE>
 
     Signature                           Title               Date
     ---------                           -----               ----

(iii)  Board of Directors:


      /s/ Steven C. Walske               Director          June 5, 1998
     ---------------------                                             
     Steven C. Walske


      /s/ C. Richard Harrison            Director          May 20, 1998
     ------------------------                                          
     C. Richard Harrison


      /s/ Robert N. Goldman              Director          June 5, 1998
     ----------------------                                            
     Robert N. Goldman


      /s/ Donald K. Grierson             Director          May 20, 1998
     -----------------------                                           
     Donald K. Grierson


      /s/ Noel G. Posternak              Director          June 5, 1998
     ----------------------                                            
     Noel G. Posternak


      /s/ Michael E. Porter              Director          June 5, 1998
     ----------------------                                            
     Michael E. Porter


      /s/ Oscar B. Marx, III             Director          June 5, 1998
     -----------------------                                           
     Oscar B. Marx, III

                                       4
<PAGE>
 
                                 EXHIBIT INDEX

<TABLE> 
<CAPTION> 
Exhibit
Number    Description                                                   Page
------    -----------                                                   ----

<S>       <C>                                                           <C>
 
4.1(a)    Restated Articles of Organization. Filed                        *
          as Exhibit 3.1 to the Quarterly Report on
          Form 10-Q for the fiscal quarter ended
          March 30, 1996 and incorporated herein
          by reference.
 
4.1(b)    Articles of Amendment to Restated Articles                      *
          of Organization of the Registrant.  Filed as
          Exhibit 4.1(b) to the Company's Registration
          Statement on Form S-8 (File No. 333-22169) and
          incorporated herein by reference).
 
4.2       By-Laws, as amended and restated, of the                        *
          Registrant.  Filed as Exhibit 3.2 to the
          Annual Report on Form 10-K for the fiscal
          year ended September 30, 1996 and
          incorporated herein by reference.
 
5.1       Opinion of Palmer & Dodge as to the legality of the             6
          securities registered hereunder.
 
23.1      Consent of Palmer & Dodge (included in Exhibit 5.1).
 
23.2      Consent of Coopers & Lybrand L.L.P.                             7
 
23.3      Consent of Price Waterhouse LLP                                 8
 
23.4      Consent of Arthur Andersen LLP                                  9

24.1      Power of Attorney (contained on the signature page hereto).

</TABLE> 
 
-----------------------
* Incorporated by reference

                                       5
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 11023}]
{"company-data": {"conformed-name": "PARAMETRIC TECHNOLOGY CORP", "cik": "0000857005", "assigned-sic": "7372", "irs-number": "042866152", "state-of-incorporation": "MA", "fiscal-year-end": "0930"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-56287", "film-number": "98643953"}, "business-address": {"street1": "128 TECHNOLOGY DR", "city": "WALTHAM", "state": "MA", "zip": "02154", "phone": "7813985000"}, "mail-address": {"street1": "128 TECHNOLOGY CORP", "city": "WALTHAM", "state": "MA", "zip": "02154"}}
As filed with the Securities and Exchange Commission
                                on June 8, 1998

                                         Registration No. ______________________

--------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                       PARAMETRIC TECHNOLOGY CORPORATION
--------------------------------------------------------------------------------
            (Exact name of registrant as specified in its charter)

            Massachusetts                                     04-2866152
            -------------                                     ----------
(State or other jurisdiction of                             (I.R.S. Employer
incorporation or organization)                              Identification No.)

                   128 Technology Drive, Waltham, MA              02154
                   ---------------------------------              -----
                   (Address of Principal Executive Offices)     (Zip Code)

                      1997 NONSTATUTORY STOCK OPTION PLAN
                      -----------------------------------
                             (Full title of Plan)

                                Edwin J. Gillis
                     Executive Vice President of Finance &
                       Administration, CFO and Treasurer
                       Parametric Technology Corporation
                             128 Technology Drive
                         Waltham, Massachusetts 02154
                         ----------------------------
                    (Name and address of agent for service)

                                (781) 398-5000
                                --------------
                  (Telephone number, including area code, of
                              agent for service)

                        CALCULATION OF REGISTRATION FEE
                        -------------------------------
Proposed          Proposed
Title of securities       Amount to be      maximum offering  maximum aggregate     Amount of
to be registered           registered       price per share    offering price    registration fee
---------------------  -------------------  ----------------  -----------------  ----------------
Common Stock,          12,000,000 shares (1)       $30.375 (2)   $364,500,000 (2)     $107,527.50
$.01 par value
--------------------------------------------------------------------------------
(1)  This Registration Statement registers shares to be offered by Registrant
pursuant to its 1997 Nonstatutory Stock Option Plan.

(2)  Estimated solely for the purpose of calculating the registration fee in
accordance with Rule 457(h) under the Securities Act of 1933, and based on the
average of the high and low sale prices of the Common Stock as reported by the
Nasdaq Stock Market's National Market on June 1, 1998.

                               Page 1 of 9 Pages
                            Exhibit Index on Page 5
STATEMENT REGARDING INCORPORATION BY REFERENCE FROM EFFECTIVE REGISTRATION
STATEMENT.

  Pursuant to General Instruction E to Form S-8, the contents of the
Registration Statement on Form S-8 of Parametric Technology Corporation (the
"Company"), as filed with the Securities and Exchange Commission (the
"Commission") on June 4, 1997 (Commission File No. 333-28495) (the "Original
Registration Statement"), relating to the registration of 5,000,000 shares of
the Company's Common Stock, $.01 par value per share (the "Common Stock"),
authorized for issuance under the Company's 1997 Nonstatutory Stock Option Plan
(the "1997 Plan"), is incorporated by reference in its entirety herein.  Since
the filing of the Original Registration Statement, one Registration Statement on
Form S-8 has been filed with the Commission on October 24, 1997 (Commission File
No. 333-38629) relating to the registration of 1,200,000 additional shares of
Common Stock for issuance under the 1997 Plan.  This Registration Statement
provides for the registration of an additional 12,000,000 shares of Common Stock
authorized for issuance under the 1997 Plan.  All Common Stock share numbers in
this Form S-8 have been adjusted to reflect the one-for-one stock dividend on
all issued and outstanding shares of Common Stock (excluding shares held in the
Company's treasury) declared by the Company's Board of Directors on February 12,
1998 and effective on March 6, 1998.

                                       2
SIGNATURES
                                   ----------

  Pursuant to the requirements of the Securities Act of 1933, as amended, 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 Waltham, Massachusetts, on the 5th day of June, 1998.

                                    PARAMETRIC TECHNOLOGY CORPORATION

                                    
                                    By: /s/ Steven C. Walske
                                       ---------------------
                                       Steven C. Walske
                                       Chief Executive Officer 
                                        and Chairman of the Board

                               POWER OF ATTORNEY
                               -----------------

          We, the undersigned officers and directors of Parametric Technology
Corporation, hereby severally constitute C. Richard Harrison, Edwin J. Gillis,
Martha L. Durcan, Esq., and Mathew C. Dallett, Esq., and each of them singly,
our true and lawful attorneys with full power to them, and each of them singly,
to sign for us and in our names in the capacities indicated below, the
Registration Statement on Form S-8 filed herewith and any and all subsequent
amendments to said Registration Statement, and generally to do all such things
in our names and behalf in our capacities as officers and directors to enable
Parametric Technology Corporation to comply with all requirements of the
Securities and Exchange Commission, hereby ratifying and confirming our
signatures as they may be signed by said attorneys, or any of them, to said
registration statement and any and all amendments thereto.

          WITNESS our hands and common seal on the date set forth below.

          Pursuant to the requirements of the Securities Act of 1933, as
amended, this Registration Statement has been signed below by the following
persons in the capacities and on the dates indicated.

     Signature                           Title                        Date
     ---------                           -----                        ----

(i)  Principal Executive Officer:

      /s/ Steven C. Walske               Chief Executive           June 5, 1998
     ---------------------               Officer and Chairman 
     Steven C. Walske                    of the Board

(ii) Principal Financial and Accounting Officer:

      /s/ Edwin J. Gillis                Executive Vice            June 5, 1998
     --------------------                President of Finance 
     Edwin J. Gillis                     & Administration, 
                                         Chief Financial Officer 
                                         and Treasurer

                                       3
Signature                           Title               Date
     ---------                           -----               ----

(iii)  Board of Directors:

      /s/ Steven C. Walske               Director          June 5, 1998
     ---------------------                                             
     Steven C. Walske

      /s/ C. Richard Harrison            Director          May 20, 1998
     ------------------------                                          
     C. Richard Harrison

      /s/ Robert N. Goldman              Director          June 5, 1998
     ----------------------                                            
     Robert N. Goldman

      /s/ Donald K. Grierson             Director          May 20, 1998
     -----------------------                                           
     Donald K. Grierson

      /s/ Noel G. Posternak              Director          June 5, 1998
     ----------------------                                            
     Noel G. Posternak

      /s/ Michael E. Porter              Director          June 5, 1998
     ----------------------                                            
     Michael E. Porter

      /s/ Oscar B. Marx, III             Director          June 5, 1998
     -----------------------                                           
     Oscar B. Marx, III

                                       4
EXHIBIT INDEX
Exhibit
Number    Description                                                   Page
------    -----------                                                   ----
4.1(a)    Restated Articles of Organization. Filed                        *
          as Exhibit 3.1 to the Quarterly Report on
          Form 10-Q for the fiscal quarter ended
          March 30, 1996 and incorporated herein
          by reference.
 
4.1(b)    Articles of Amendment to Restated Articles                      *
          of Organization of the Registrant.  Filed as
          Exhibit 4.1(b) to the Company's Registration
          Statement on Form S-8 (File No. 333-22169) and
          incorporated herein by reference).
 
4.2       By-Laws, as amended and restated, of the                        *
          Registrant.  Filed as Exhibit 3.2 to the
          Annual Report on Form 10-K for the fiscal
          year ended September 30, 1996 and
          incorporated herein by reference.
 
5.1       Opinion of Palmer & Dodge as to the legality of the             6
          securities registered hereunder.
 
23.1      Consent of Palmer & Dodge (included in Exhibit 5.1).
 
23.2      Consent of Coopers & Lybrand L.L.P.                             7
 
23.3      Consent of Price Waterhouse LLP                                 8
 
23.4      Consent of Arthur Andersen LLP                                  9

24.1      Power of Attorney (contained on the signature page hereto).
-----------------------
* Incorporated by reference

                                       5