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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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                                    FORM 8-K

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                                 CURRENT REPORT
                       PURSUANT TO SECTION 13 OR 15(d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934

         Date of Report (Date of earliest event reported): July 8, 2005

                                 GSI GROUP INC.
             (Exact name of registrant as specified in its charter)

                              New Brunswick, Canada
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                 (State or other jurisdiction of incorporation)

            000-25705                                 98-0110412
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     (Commission File Number)           (I.R.S. Employer Identification No.)

                 39 Manning Road, Billerica, Massachusetts 01821
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          (Address of principal executive offices, including zip code)

                                 (978) 439-5511
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              (Registrant's telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

[ ]   Written communications pursuant to Rule 425 under the Securities Act (17
      CFR 220.425)

[ ]   Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17
      CFR 240.14a-12)

[ ]   Pre-commencement communications pursuant to Rule 14d-2(b) under the
      Exchange Act (17 CFR 240.14d-2(b))

[ ]   Pre-commencement communications pursuant to Rule 13e-4(c) under the
      Exchange Act (17 CFR 240.13e-4(c))

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ITEM 1.01.  ENTRY INTO A MATERIAL DEFINITIVE AGREEMENT.

      Effective June 8, 2005 GSI Lumonics Corporation ("Company"), a wholly
owned subsidiary of GSI Group Inc., entered into a Real Estate Purchase and Sale
Agreement ("Agreement") with STAG Capital Partners, LLC ("Purchaser") for the
sale of land and a building located at 22300 Haggerty Road, Farmington Hills,
Michigan ("Property"). For a period of thirty days from the Agreement, the
Purchaser entered into a study period ("Study Period") during which the
Purchaser may have backed out of the Agreement for any reason. At the end of the
Study Period, the Purchaser notified the company that they will proceed with the
transaction. On July 8, 2005, the Company and the Purchaser entered into a First
Amendment to the Agreement ("Amendment"). The material terms of the Agreement
and the Amendment are:

1.    Purchase Price: $6,515,000, net of certain closing costs. A deposit of
$50,000 upon signing the Agreement, fully refundable until end of the thirty day
Study Period, an additional $50,000 if Buyer decides to proceed at end of Study
Period.

2.    Closing Date: fifteen days after the "Rent Commencement Date" as defined
in the lease dated February 11, 2005 ("Lease") between the Company and SEWS-DTC
Inc. ("Tenant") for the Property.

3.    Conditions: The sale is contingent upon the Company satisfying certain 
closing conditions, all of which the Company expects to be able to satisfy.

4.    Company Representations: "As Is" sale regarding the building. The Company
represents that the Lease is in effect and is in accordance with the documents
provided to Purchaser.


ITEM 9.01.  FINANCIAL STATEMENTS AND EXHIBITS.

      (a)   Financial Statements of Businesses Acquired.
            Not required.

      (b)   Pro Forma Financial Information.
            Not required.

      (c)   Exhibits.

            10.1  Real Estate Purchase and Sale Agreement Between GSI Lumonics
                  Corporation and STAG Capital Partners, LLC

            10.2  First Amendment to Real Estate Purchase and Sale Agreement



                                    SIGNATURE

      Pursuant to the requirements of the Securities Exchange Act of 1934, as
amended, the Registrant has duly caused this report to be signed on its behalf
by the undersigned hereunto duly authorized.

                                    GSI GROUP INC.
                                    (Registrant)

Date: July 13, 2005             By: /s/ Thomas R. Swain
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                                    Thomas R. Swain
                                    Vice President, Finance and Chief Financial
                                          Officer



                                  EXHIBIT INDEX



Exhibit No.                              Description
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   10.1          Real Estate Purchase and Sale Agreement Between GSI Lumonics
                 Corporation and STAG Capital Partners, LLC

   10.2          First Amendment to Real Estate Purchase and Sale Agreement