<PAGE>

                      SECURITIES AND EXCHANGE COMMISSION
                             Washington, DC  20549
                               ________________
                                   FORM S-8
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933
                               ________________
                               GSI LUMONICS INC.
            (Exact name of registrant as specified in its charter)

     NEW BRUNSWICK, CANADA                             98-0110412
  (State or other jurisdiction              (IRS Employer Identification No.)
of incorporation or organization)

             105 SCHNEIDER ROAD, KANATA, ONTARIO, CANADA  K2K 1Y3
              (Address of principal executive offices) (Zip code)
                               ________________
                GSI LUMONICS INC. EMPLOYEE STOCK PURCHASE PLAN
                           (Full title of the plan)
                               ________________

                              Charles D. Winston
                                39 Manning Road
                             Billerica, MA  01821
                                (978) 439-5511
                    (Name and address of agent for service)
         (Telephone number, including area code, of agent for service)

                                   Copy to:
           Eileen Casal                              Mark L. Weissler
      V.P. & General Counsel               Milbank, Tweed, Hadley & McCloy LLP
        GSI Lumonics Inc.                       One Chase Manhattan Plaza
        105 Schneider Road                      New York, New York  10005
 Kanata, Ontario, Canada  K2K 1Y3                     (212) 530-5000
          (613) 592-1460
                                ________________
                        CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------
     Title of Each Class of       Amount to Be  Proposed Maximum  Proposed Maximum     Amount of
 Securities to Be Registered       Registered    Offering Price      Aggregate      Registration Fee
                                                  Per Share *     Offering Price*
----------------------------------------------------------------------------------------------------
<S>                               <C>           <C>               <C>               <C>
Common Stock, no par value......       300,000       $8.38            $2,514,000           $629
====================================================================================================
</TABLE>

* Estimated solely for the purpose of calculating the registration fee in
  accordance with Rule 457(h) under the Securities Act of 1933, as amended.
<PAGE>

                                    PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.   Incorporation of Documents by Reference

          We hereby incorporate by reference in this registration statement the
following documents:

          (1)  our annual report on Form 10-K for the year ended December 31,
               2000;

          (2)  our quarterly reports on Form 10-Q for the periods ended March
               30, 2001, June 29, 2001 and September 28, 2001; and

          (3)  the description of our common stock incorporated by reference in
               our registration statement on Form 8-A12G declared effective by
               the Securities and Exchange Commission April 2, 1999.

          In addition, all documents subsequently filed by us pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as
amended, prior to the filing of a post-effective amendment which indicates that
all securities offered hereby have been sold or which deregisters 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

          Subject to Section 81 of the Business Corporations Act, New Brunswick,
as from time to time amended, except in respect of an action by or on behalf of
the registrant or Another Body Corporate (as defined below) to procure a
judgment in its favor, the registrant must indemnify each director and officer
and each former director and officer and each person who acts or acted at the
registrant's request as a director or officer of Another Body Corporate, and his
heirs and legal representatives, against all costs, charges and expenses,
including any amount paid to settle an action or satisfy a judgment, reasonably
incurred by him in respect of any civil, criminal or administrative action or
proceeding to which he is made a party by reason of being or having been a
director or officer of the Corporation or Another Body Corporate, as the case
may be, if

          (a)  he acted honestly and in good faith with a view to the best
     interests of the registrant; and
<PAGE>

          (b)  in the case of a criminal or administrative action or proceeding
     that is enforced by a monetary penalty, he had reasonable grounds for
     believing that his conduct was lawful.

"Another Body Corporate" as used herein means a body corporate of which the
registrant is or was a shareholder or creditor.

We maintain directors' and officers' liability insurance.

ITEM 7.   EXEMPTION FROM REGISTRATION CLAIMED

          Not applicable.

ITEM 8.   EXHIBITS

     4.1  GSI Lumonics Inc. Employee Stock Purchase Plan.

     5.1  Opinion of Stewart McKelvey Stirling Scales regarding the legality of
          the shares being registered, including consent.

    23.1  Consent of Stewart McKelvey Stirling Scales (included in Exhibit 5.1).

    23.2  Consent of Ernst & Young LLP, independent public accountants.

    24.1  Power of Attorney (included in signature pages).

ITEM 9.   UNDERTAKINGS

          (a)  The undersigned registrant hereby undertakes:

          (1)  To file, during any period in which offers or sales are being
     made, a post-effective amendment to this registration statement;

               (i)    To include any prospectus required by Section 10(a)(3) of
     the Securities Act of 1933, as amended;

               (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. Notwithstanding the foregoing, any increase or
     decrease in volume of securities offered (if the total dollar value of
     securities offered would not exceed that which was registered) and any
     deviation from the low or high end of the estimated maximum offering range
     may be reflected in the form of prospectus filed with the Securities and
     Exchange Commission pursuant to Rule 424(b) if, in the aggregate, the
     changes in volume and price represent no more than a 20 percent change in
     the maximum aggregate offering price set forth in the "Calculation of
     Registration Fee" table in the effective registration statement; and

                                     II-2
<PAGE>

               (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 (a)(1)(i) and (a)(1)(ii) of this section
     do not apply if the information required to be included in a post-effective
     amendment by those paragraphs is contained in periodic reports filed with
     or furnished to the Securities and Exchange Commission by the registrant
     pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934, as
     amended, that are incorporated by reference in the registration statement.

          (2)  That, for the purpose of determining any liability under the
     Securities Act of 1933, as amended, each such post-effective amendment
     shall be deemed to be a new registration statement relating to the
     securities offered therein, and the offering of such securities at that
     time shall be deemed to be the initial bona fide offering thereof.

          (3)  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.

          (b)  The undersigned registrant hereby undertakes that, for purposes
     of determining any liability under the Securities Act of 1933, as amended,
     each filing of the registrant's annual report pursuant to Section 13(a) or
     15(d) of the Securities Exchange Act of 1934, as amended (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, as
     amended), that is incorporated by reference in the registration statement
     shall be deemed to be a new registration statement relating to the
     securities offered therein, and the offering of such securities at that
     time shall be deemed to be the initial bona fide offering thereof.

          (c)  Insofar as indemnification for liabilities arising under the
     Securities Act of 1933, as amended, 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
<PAGE>

                                   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 Ottawa, Province of Ontario, on November 16, 2001.

                                   GSI LUMONICS INC.

                                   By: /s/ Charles D. Winston
                                       ----------------------
                                       Name:  Charles D. Winston
                                       Title: Chief Executive Officer

                               POWER OF ATTORNEY

          Each person whose signature appears below hereby appoints Charles D.
Winston and Wayne T. Penney and each of them severally, acting alone and without
the other, his true and lawful attorney-in-fact with the authority to execute in
the name of each such person, and to file with the Securities and Exchange
Commission, together with any exhibits thereto and other documents therewith,
any and all amendments (including without limitation post-effective amendments)
to this registration statement on Form S-8 necessary or advisable to enable the
registrant to comply with the Securities Act of 1933, as amended, and any rules,
regulations, and requirements of the Securities and Exchange Commission in
respect thereof, which amendments may make such other changes in the
Registration Statement as the aforesaid attorney-in-fact executing the same
deems appropriate.

          Pursuant to the requirements of the Securities Act of 1933 this
registration statement has been signed by the following persons in the
capacities and on the dates indicated.

<TABLE>
<CAPTION>
          Signature                               Title                             Date
------------------------------  ------------------------------------------  --------------------
<S>                             <C>                                         <C>
/s/ Charles D. Winston          Director and Chief Executive Officer and    November 16, 2001
------------------------------  authorized representative in the United
Charles D. Winston              States
                                (Principal Executive Officer)

/s/ Thomas R. Swain             Vice President Finance and Chief            November 16, 2001
------------------------------  Financial Officer
Thomas R. Swain                 (Principal Financial and Accounting
                                Officer)

/s/ Richard B. Black            Director                                    November 16, 2001
------------------------------
Richard B. Black

/s/ Paul F. Ferrari             Director                                    November 16, 2001
------------------------------
Paul F. Ferrari
</TABLE>

                                     II-4
<PAGE>

<TABLE>
<CAPTION>
          Signature                               Title                             Date
------------------------------  ------------------------------------------  --------------------
<S>                             <C>                                         <C>

/s/ Byron O. Pond               Director                                    November 16, 2001
------------------------------
Byron O. Pond

/s/ Benjamin J. Virgilio        Director                                    November 16, 2001
------------------------------
Benjamin J. Virgilio

/s/ Phillip A. Griffiths        Director                                    November 16, 2001
------------------------------
Phillip A. Griffiths
</TABLE>

                                     II-5
<PAGE>

                                 EXHIBIT INDEX

Exhibit No   Description

     4.1  GSI Lumonics Inc. Employee Stock Purchase Plan.

     5.1  Opinion of Stewart McKelvey Stirling Scales regarding the legality of
          the shares being registered, including consent.

    23.1  Consent of Stewart McKelvey Stirling Scales (included in Exhibit
          5.1).

    23.2  Consent of Ernst & Young LLP, independent public accountants.

    24.1  Power of Attorney (included in signature pages).

                                       1
[{"type": "S-8", "sequence": "1", "filename": "ds8.txt", "description": "EMPLOYEE STOCK PURCHASE PLAN", "secsgml_size_bytes": 15211}]
{"company-data": {"conformed-name": "GSI LUMONICS INC", "cik": "0001076930", "assigned-sic": "3559", "irs-number": "381859358", "state-of-incorporation": "A3", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-73666", "film-number": "1795461"}, "business-address": {"street1": "105 SCHNEIDER RD KANATA", "street2": "ONTARIO CANADA", "city": "K2K 1Y3", "state": "A6", "zip": "00000"}, "mail-address": {"street1": "105 SCHNEIDER RD KANATA", "street2": "ONTARIO CANADA", "city": "K2K 1Y3"}, "former-company": [{"former-conformed-name": "GSI LUMONICS", "date-changed": "19990331"}, {"former-conformed-name": "LUMONICS INC", "date-changed": "19990115"}]}
SECURITIES AND EXCHANGE COMMISSION
                             Washington, DC  20549
                               ________________
                                   FORM S-8
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933
                               ________________
                               GSI LUMONICS INC.
            (Exact name of registrant as specified in its charter)

     NEW BRUNSWICK, CANADA                             98-0110412
  (State or other jurisdiction              (IRS Employer Identification No.)
of incorporation or organization)

             105 SCHNEIDER ROAD, KANATA, ONTARIO, CANADA  K2K 1Y3
              (Address of principal executive offices) (Zip code)
                               ________________
                GSI LUMONICS INC. EMPLOYEE STOCK PURCHASE PLAN
                           (Full title of the plan)
                               ________________

                              Charles D. Winston
                                39 Manning Road
                             Billerica, MA  01821
                                (978) 439-5511
                    (Name and address of agent for service)
         (Telephone number, including area code, of agent for service)

                                   Copy to:
           Eileen Casal                              Mark L. Weissler
      V.P. & General Counsel               Milbank, Tweed, Hadley & McCloy LLP
        GSI Lumonics Inc.                       One Chase Manhattan Plaza
        105 Schneider Road                      New York, New York  10005
 Kanata, Ontario, Canada  K2K 1Y3                     (212) 530-5000
          (613) 592-1460
                                ________________
                        CALCULATION OF REGISTRATION FEE
----------------------------------------------------------------------------------------------------
     Title of Each Class of       Amount to Be  Proposed Maximum  Proposed Maximum     Amount of
 Securities to Be Registered       Registered    Offering Price      Aggregate      Registration Fee
                                                  Per Share *     Offering Price*
----------------------------------------------------------------------------------------------------
Common Stock, no par value......       300,000       $8.38            $2,514,000           $629
====================================================================================================
* Estimated solely for the purpose of calculating the registration fee in
  accordance with Rule 457(h) under the Securities Act of 1933, as amended.
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.   Incorporation of Documents by Reference

          We hereby incorporate by reference in this registration statement the
following documents:

          (1)  our annual report on Form 10-K for the year ended December 31,
               2000;

          (2)  our quarterly reports on Form 10-Q for the periods ended March
               30, 2001, June 29, 2001 and September 28, 2001; and

          (3)  the description of our common stock incorporated by reference in
               our registration statement on Form 8-A12G declared effective by
               the Securities and Exchange Commission April 2, 1999.

          In addition, all documents subsequently filed by us pursuant to
Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as
amended, prior to the filing of a post-effective amendment which indicates that
all securities offered hereby have been sold or which deregisters 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

          Subject to Section 81 of the Business Corporations Act, New Brunswick,
as from time to time amended, except in respect of an action by or on behalf of
the registrant or Another Body Corporate (as defined below) to procure a
judgment in its favor, the registrant must indemnify each director and officer
and each former director and officer and each person who acts or acted at the
registrant's request as a director or officer of Another Body Corporate, and his
heirs and legal representatives, against all costs, charges and expenses,
including any amount paid to settle an action or satisfy a judgment, reasonably
incurred by him in respect of any civil, criminal or administrative action or
proceeding to which he is made a party by reason of being or having been a
director or officer of the Corporation or Another Body Corporate, as the case
may be, if

          (a)  he acted honestly and in good faith with a view to the best
     interests of the registrant; and
(b)  in the case of a criminal or administrative action or proceeding
     that is enforced by a monetary penalty, he had reasonable grounds for
     believing that his conduct was lawful.

"Another Body Corporate" as used herein means a body corporate of which the
registrant is or was a shareholder or creditor.

We maintain directors' and officers' liability insurance.

ITEM 7.   EXEMPTION FROM REGISTRATION CLAIMED

          Not applicable.

ITEM 8.   EXHIBITS

     4.1  GSI Lumonics Inc. Employee Stock Purchase Plan.

     5.1  Opinion of Stewart McKelvey Stirling Scales regarding the legality of
          the shares being registered, including consent.

    23.1  Consent of Stewart McKelvey Stirling Scales (included in Exhibit 5.1).

    23.2  Consent of Ernst & Young LLP, independent public accountants.

    24.1  Power of Attorney (included in signature pages).

ITEM 9.   UNDERTAKINGS

          (a)  The undersigned registrant hereby undertakes:

          (1)  To file, during any period in which offers or sales are being
     made, a post-effective amendment to this registration statement;

               (i)    To include any prospectus required by Section 10(a)(3) of
     the Securities Act of 1933, as amended;

               (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. Notwithstanding the foregoing, any increase or
     decrease in volume of securities offered (if the total dollar value of
     securities offered would not exceed that which was registered) and any
     deviation from the low or high end of the estimated maximum offering range
     may be reflected in the form of prospectus filed with the Securities and
     Exchange Commission pursuant to Rule 424(b) if, in the aggregate, the
     changes in volume and price represent no more than a 20 percent change in
     the maximum aggregate offering price set forth in the "Calculation of
     Registration Fee" table in the effective registration statement; and

                                     II-2
(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 (a)(1)(i) and (a)(1)(ii) of this section
     do not apply if the information required to be included in a post-effective
     amendment by those paragraphs is contained in periodic reports filed with
     or furnished to the Securities and Exchange Commission by the registrant
     pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934, as
     amended, that are incorporated by reference in the registration statement.

          (2)  That, for the purpose of determining any liability under the
     Securities Act of 1933, as amended, each such post-effective amendment
     shall be deemed to be a new registration statement relating to the
     securities offered therein, and the offering of such securities at that
     time shall be deemed to be the initial bona fide offering thereof.

          (3)  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.

          (b)  The undersigned registrant hereby undertakes that, for purposes
     of determining any liability under the Securities Act of 1933, as amended,
     each filing of the registrant's annual report pursuant to Section 13(a) or
     15(d) of the Securities Exchange Act of 1934, as amended (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, as
     amended), that is incorporated by reference in the registration statement
     shall be deemed to be a new registration statement relating to the
     securities offered therein, and the offering of such securities at that
     time shall be deemed to be the initial bona fide offering thereof.

          (c)  Insofar as indemnification for liabilities arising under the
     Securities Act of 1933, as amended, 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
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 Ottawa, Province of Ontario, on November 16, 2001.

                                   GSI LUMONICS INC.

                                   By: /s/ Charles D. Winston
                                       ----------------------
                                       Name:  Charles D. Winston
                                       Title: Chief Executive Officer

                               POWER OF ATTORNEY

          Each person whose signature appears below hereby appoints Charles D.
Winston and Wayne T. Penney and each of them severally, acting alone and without
the other, his true and lawful attorney-in-fact with the authority to execute in
the name of each such person, and to file with the Securities and Exchange
Commission, together with any exhibits thereto and other documents therewith,
any and all amendments (including without limitation post-effective amendments)
to this registration statement on Form S-8 necessary or advisable to enable the
registrant to comply with the Securities Act of 1933, as amended, and any rules,
regulations, and requirements of the Securities and Exchange Commission in
respect thereof, which amendments may make such other changes in the
Registration Statement as the aforesaid attorney-in-fact executing the same
deems appropriate.

          Pursuant to the requirements of the Securities Act of 1933 this
registration statement has been signed by the following persons in the
capacities and on the dates indicated.
Signature                               Title                             Date
------------------------------  ------------------------------------------  --------------------
/s/ Charles D. Winston          Director and Chief Executive Officer and    November 16, 2001
------------------------------  authorized representative in the United
Charles D. Winston              States
                                (Principal Executive Officer)

/s/ Thomas R. Swain             Vice President Finance and Chief            November 16, 2001
------------------------------  Financial Officer
Thomas R. Swain                 (Principal Financial and Accounting
                                Officer)

/s/ Richard B. Black            Director                                    November 16, 2001
------------------------------
Richard B. Black

/s/ Paul F. Ferrari             Director                                    November 16, 2001
------------------------------
Paul F. Ferrari
II-4
Signature                               Title                             Date
------------------------------  ------------------------------------------  --------------------
/s/ Byron O. Pond               Director                                    November 16, 2001
------------------------------
Byron O. Pond

/s/ Benjamin J. Virgilio        Director                                    November 16, 2001
------------------------------
Benjamin J. Virgilio

/s/ Phillip A. Griffiths        Director                                    November 16, 2001
------------------------------
Phillip A. Griffiths
II-5
EXHIBIT INDEX

Exhibit No   Description

     4.1  GSI Lumonics Inc. Employee Stock Purchase Plan.

     5.1  Opinion of Stewart McKelvey Stirling Scales regarding the legality of
          the shares being registered, including consent.

    23.1  Consent of Stewart McKelvey Stirling Scales (included in Exhibit
          5.1).

    23.2  Consent of Ernst & Young LLP, independent public accountants.

    24.1  Power of Attorney (included in signature pages).

                                       1