<PAGE>   1
     As filed with the Securities and Exchange Commission on September 8, 1997


                                                           Registration No. 333-


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549



                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933




                               GARTNER GROUP, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

           Delaware                                              06-3099750
(STATE OR OTHER JURISDICTION OF                               (I.R.S. EMPLOYER
INCORPORATION OR ORGANIZATION)                               IDENTIFICATION NO.)


                                 P.O. Box 10212
                               56 Top Gallant Road
                             Stamford, CT 06904-2212
                                 (203) 964-0096
                   (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE
             NUMBER, INCLUDING AREA CODE, OF REGISTRANT'S PRINCIPAL
                               EXECUTIVE OFFICES)



              Gartner Group, Inc. 1996 Long Term Stock Option Plan
                            (FULL TITLE OF THE PLAN)



                                John F. Halligan
         Executive Vice President, Chief Financial Officer and Secretary
                               Gartner Group, Inc.
                                 P.O. Box 10212
                               56 Top Gallant Road
                             Stamford, CT 06904-2212
                                 (203) 964-0096
            (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER,
                   INCLUDING AREA CODE, OF AGENT FOR SERVICE)



                                    Copy to:

                              Frank J. Marco, Esq.
                              Shipman & Goodwin LLP
                                One American Row
                               Hartford, CT 06103
                                 (860) 251-5000

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
                                                          PROPOSED            PROPOSED
                                                           MAXIMUM             MAXIMUM
     TITLE OF EACH CLASS               AMOUNT             OFFERING            AGGREGATE           AMOUNT OF
     OF SECURITIES TO BE               TO BE              PRICE PER           OFFERING           REGISTRATION
          REGISTERED                 REGISTERED             SHARE             PRICE (1)              FEE
- ----------------------------------------------------------------------------------------------------------------
<S>                               <C>                      <C>               <C>                  <C>
Common Stock, Class A, par        1,800,000 shares         $20.86            $37,548,000           $11,378.18
value $0.0005
- ----------------------------------------------------------------------------------------------------------------
</TABLE>

(1)   Estimated solely for the purpose of calculating the registration fee.
      Pursuant to Rule 457(h), the proposed maximum offering price per share is
      based on the weighted average exercise price of outstanding options to
      purchase 1,800,000 shares.
<PAGE>   2
                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

         The information statement being delivered by Gartner Group, Inc. (the
"Company") to participants in the Company's 1996 Long Term Stock Option Plan
(the "Plan"), as required by Rule 428 under the Securities Act of 1933, as
amended (the "Securities Act"), has been prepared in accordance with the
requirements of Form S-8 and relates to shares of common stock, par value
$0.0005 per share, (the "Shares") to be issued pursuant to the Plan. The
information with respect to the Plan required in the Section 10(a) prospectus is
included in documents being maintained and delivered by the Company as required
by Rule 428 under the Securities Act. The Company shall provide to participants
a written statement advising them of the availability without charge, upon
written or oral request, of documents incorporated by reference herein, as is
required by Item 2 of Part I of Form S-8.
<PAGE>   3
                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents, previously filed with the Commission, are
hereby incorporated by reference in this registration statement:

         (a) The Company's Annual Report on Form 10-K for the year ended
September 30, 1996;

         (b) All other reports filed pursuant to Section 13(a) or 15(d) of the
Securities Exchange Act of 1934, as amended (the "Exchange Act") since the end
of the fiscal year covered by the document referred to in (a) above; and

         (c) The description of the Shares contained in the Registration
Statement on Form 8-A filed on August 18, 1993, filed pursuant to Section 12(g)
of the Exchange Act, including any amendment or report filed for the purpose of
updating such description.

         In addition, all documents subsequently filed by the Company pursuant
to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date of
this Registration Statement and prior to the filing of a post-effective
amendment which indicates that all securities offered hereby have been sold or
which deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference in this registration statement and to be a part hereof
from the date of filing of such documents. Any statement contained in a document
incorporated or deemed to be incorporated by reference in this registration
statement shall be deemed to be modified or superseded for purposes of this
registration statement to the extent that a statement contained herein or in any
other subsequently filed document which also is or is deemed to be incorporated
by reference herein modifies or supersedes such statement. Any such statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this registration statement.


ITEM 4.  DESCRIPTION OF SECURITIES.

         This item is not applicable.


                                      II-1
<PAGE>   4
ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         This item is not applicable.


ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the Delaware General Corporation Law ("Delaware Law")
provides that a corporation may indemnify a director, officer, employee or
agent made a party to an action by reason of the fact that he was a director,
officer, employee or agent of the corporation, or was serving at the request of
the corporation, against expenses actually and reasonably incurred, including
attorneys' fees, in connection with such action, if he acted in good faith and
in a manner he reasonably believed to be in, or not opposed to, the best
interests of the corporation and, with respect to any criminal action, had no
reasonable cause to believe his conduct was unlawful.

         The Company's Certificate of Incorporation limits, to the maximum
extent permitted by Delaware Law, the personal liability of a director to the
Company or its shareholders for monetary damages for breach of fiduciary duty
as a director. The Company's By-laws provide that the Company shall indemnify
its officers and directors to the fullest extent permitted by Delaware Law
against all expense, liability and loss, including attorney's fees, actually
and reasonably incurred and may purchase and maintain insurance against any
liability asserted and incurred by reason of serving as such, whether or not the
Company has the power to indemnify against such liability. The Company has
entered into indemnification agreements with its officers and directors
containing provisions which are in some respects broader than the specific
indemnification provisions contained in Delaware Law and which require that, to
the extent the Company maintains liability insurance applicable to officers or
directors, each officer and director shall be covered by such policies to the
same extent as are accorded the most favorably insured of the Company's
officers or directors, as the case may be.

         Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers or persons controlling
the Company pursuant to the foregoing provisions and agreements, the Company
has been informed that in the opinion of the staff of the Commission such
indemnification is against public policy as expressed in the Securities Act
and is therefore unenforceable.
  
ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         This item is not applicable.


                                      II-2
<PAGE>   5
ITEM 8.  EXHIBITS.

         The following exhibits are filed as part of this Registration Statement
or incorporated by reference herein:


<TABLE>
<CAPTION>
Exhibit Number                      Description of Exhibits
- --------------                      -----------------------
<S>                        <C>
         4.1(a)            Restated Certificate of Incorporation of the Company (filed as Exhibit 3.1
                           to the Company's Annual Report on Form 10-K (File No. 0-15144) for the year
                           ended September 30, 1995 and incorporated herein by reference).

         4.1(b)*           Amendment dated June 19, 1995 to Restated Certificate of Incorporation of the
                           Company.

         4.1(c)*           Amendment dated March 18, 1996 to Restated Certificate of Incorporation of the
                           Company.

         4.2*              Amended By-laws of the Company, as of April 24, 1997.

         4.3               Form of certificate for the Company's common stock  (filed as Exhibit 4.2 to
                           the Company's Registration Statement on Form S-1 (File No. 33-67576) and 
                           incorporated herein by reference).

         4.4               Gartner Group, Inc. 1996 Long Term Stock Option Plan, as amended and restated on 
                           February 24, 1997 (filed as Exhibit 10.16 to the Company's Form 10-Q for the 
                           quarter ended June 30, 1997 (File No. 0-15144) and incorporated herein by
                           reference).

         5.1*              Opinion of Shipman & Goodwin LLP.

         23.1*             Independent Auditors' Consent, KPMG Peat Marwick LLP.

         23.2*             Consent of Independent Accountants, Price Waterhouse LLP
                           
         23.3*             Consent of Shipman & Goodwin LLP (included in Exhibit 5).

         24.1*             Powers of Attorney.
</TABLE>

- -------------
* Filed herewith.


                                      II-3
<PAGE>   6
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
         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.

                  (2) 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 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, each filing of the
registrant's annual report pursuant to Section 13(a) or 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
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 of 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-4
<PAGE>   7
                                   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 Stamford and State of Connecticut on the 8th
day of September, 1997.

                                      GARTNER GROUP, INC.



                                      BY  /s/   MANUEL A. FERNANDEZ*
                                        --------------------------------------
                                           MANUEL A. FERNANDEZ
                                           CHAIRMAN, PRESIDENT
                                               AND CHIEF EXECUTIVE OFFICER


         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 date indicated.

<TABLE>
<CAPTION>
           SIGNATURE                               TITLE                           DATE
           ---------                               -----                           ----
<S>                                    <C>                                     <C>
    /s/Manuel A. Fernandez*             Chairman, President and Chief           September 8, 1997
- -------------------------------         Executive Officer (principal
       MANUEL A. FERNANDEZ                   executive officer)

    /s/John F. Halligan*               Executive Vice President, Chief          September 8, 1997
- ------------------------------         Financial Officer and Secretary
       JOHN F. HALLIGAN                   (principal financial and
                                              accounting officer)

    /s/William O. Grabe*                           Director                     September 8, 1997
- ------------------------------
       WILLIAM O. GRABE


   /s/Max D. Hopper*                               Director                     September 8, 1997
- ------------------------------
      MAX D. HOPPER


   /s/John P. Imlay, Jr.*                          Director                     September 8, 1997
- ------------------------------
      JOHN P. IMLAY, JR.


  /s/Stephen G. Pagliuca*                          Director                     September 8, 1997
- ------------------------------
     STEPHEN G. PAGLIUCA
</TABLE>


                                      II-5
<PAGE>   8
<TABLE>
<S>                                    <C>                                     <C>

                                                   Director                    
- ------------------------------
      DENNIS G. SISCO


   /s/ Robert E. Weissman*                         Director                     September 8, 1997
- ------------------------------
       ROBERT E. WEISSMAN


*By:   /s/ John F. Halligan                                                     September 8, 1997
- ------------------------------
       JOHN F. HALLIGAN
       ATTORNEY-IN-FACT

</TABLE>

                                      II-6
<PAGE>   9
                                  EXHIBIT INDEX

<TABLE>
<CAPTION>
Exhibit Number                      Description of Exhibits                             Sequentially
- --------------                      -----------------------                             Numbered Page
                                                                                        -------------
<S>                        <C>                                                          <C>
         4.1(a)            Restated Certificate of Incorporation of the Company
                           (filed as Exhibit 3.1 to the Company's Annual Report
                           on Form 10-K (File No. 0-15144) for the year ended
                           September 30, 1995 and incorporated herein by
                           reference).

         4.1(b)*           Amendment dated June 19, 1995 to Restated Certificate
                           of Incorporation of the Company.
 .
         4.1(c)*           Amendment dated March 18, 1996 to Restated
                           Certificate of Incorporation of the Company.

         4.2*              Amended By-laws of the Company, as of April 24, 1997.

         4.3               Form of certificate for the Company's common stock
                           (filed as Exhibit 4.2 to the Company's Registration
                           Statement on Form S-1 (File No. 33-67576) and
                           incorporated herein by reference).

         4.4               Gartner Group, Inc. 1996 Long Term Stock Option Plan,
                           as amended and restated on February 24, 1997
                           (filed as Exhibit 10.16 to the Company's Form 10-Q
                           for the quarter ended June 30, 1997 (File No.
                           0-15144) and incorporated herein by reference).

         5.1*              Opinion of Shipman & Goodwin LLP.

         23.1*             Independent Auditors' Consent, KPMG Peat
                           Marwick LLP.

         23.2*             Consent of Independent Accountants, Price
                           Waterhouse LLP.

         23.3*             Consent of Shipman & Goodwin LLP (included in
                           Exhibit 5).

         24.1*             Powers of Attorney.
</TABLE>

- -------------
* Filed herewith.
[{"type": "S-8", "sequence": "1", "description": "S-8", "secsgml_size_bytes": 19694}]
{"company-data": {"conformed-name": "GARTNER GROUP INC", "cik": "0000749251", "assigned-sic": "8741", "irs-number": "043099750", "state-of-incorporation": "DE", "fiscal-year-end": "0930"}, "filing-values": {"form-type": "S-8", "file-number": "333-35169", "film-number": "97676941"}, "business-address": {"street1": "56 TOP GALLANT RD", "street2": "P O BOX 10212", "city": "STAMFORD", "state": "CT", "zip": "06904-2212", "phone": "2039640096"}}
1
     As filed with the Securities and Exchange Commission on September 8, 1997

                                                           Registration No. 333-

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                               GARTNER GROUP, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

           Delaware                                              06-3099750
(STATE OR OTHER JURISDICTION OF                               (I.R.S. EMPLOYER
INCORPORATION OR ORGANIZATION)                               IDENTIFICATION NO.)

                                 P.O. Box 10212
                               56 Top Gallant Road
                             Stamford, CT 06904-2212
                                 (203) 964-0096
                   (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE
             NUMBER, INCLUDING AREA CODE, OF REGISTRANT'S PRINCIPAL
                               EXECUTIVE OFFICES)

              Gartner Group, Inc. 1996 Long Term Stock Option Plan
                            (FULL TITLE OF THE PLAN)

                                John F. Halligan
         Executive Vice President, Chief Financial Officer and Secretary
                               Gartner Group, Inc.
                                 P.O. Box 10212
                               56 Top Gallant Road
                             Stamford, CT 06904-2212
                                 (203) 964-0096
            (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER,
                   INCLUDING AREA CODE, OF AGENT FOR SERVICE)

                                    Copy to:

                              Frank J. Marco, Esq.
                              Shipman & Goodwin LLP
                                One American Row
                               Hartford, CT 06103
                                 (860) 251-5000

                         CALCULATION OF REGISTRATION FEE
PROPOSED            PROPOSED
                                                           MAXIMUM             MAXIMUM
     TITLE OF EACH CLASS               AMOUNT             OFFERING            AGGREGATE           AMOUNT OF
     OF SECURITIES TO BE               TO BE              PRICE PER           OFFERING           REGISTRATION
          REGISTERED                 REGISTERED             SHARE             PRICE (1)              FEE
- ----------------------------------------------------------------------------------------------------------------
Common Stock, Class A, par        1,800,000 shares         $20.86            $37,548,000           $11,378.18
value $0.0005
- ----------------------------------------------------------------------------------------------------------------
(1)   Estimated solely for the purpose of calculating the registration fee.
      Pursuant to Rule 457(h), the proposed maximum offering price per share is
      based on the weighted average exercise price of outstanding options to
      purchase 1,800,000 shares.
2
                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

         The information statement being delivered by Gartner Group, Inc. (the
"Company") to participants in the Company's 1996 Long Term Stock Option Plan
(the "Plan"), as required by Rule 428 under the Securities Act of 1933, as
amended (the "Securities Act"), has been prepared in accordance with the
requirements of Form S-8 and relates to shares of common stock, par value
$0.0005 per share, (the "Shares") to be issued pursuant to the Plan. The
information with respect to the Plan required in the Section 10(a) prospectus is
included in documents being maintained and delivered by the Company as required
by Rule 428 under the Securities Act. The Company shall provide to participants
a written statement advising them of the availability without charge, upon
written or oral request, of documents incorporated by reference herein, as is
required by Item 2 of Part I of Form S-8.
3
                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents, previously filed with the Commission, are
hereby incorporated by reference in this registration statement:

         (a) The Company's Annual Report on Form 10-K for the year ended
September 30, 1996;

         (b) All other reports filed pursuant to Section 13(a) or 15(d) of the
Securities Exchange Act of 1934, as amended (the "Exchange Act") since the end
of the fiscal year covered by the document referred to in (a) above; and

         (c) The description of the Shares contained in the Registration
Statement on Form 8-A filed on August 18, 1993, filed pursuant to Section 12(g)
of the Exchange Act, including any amendment or report filed for the purpose of
updating such description.

         In addition, all documents subsequently filed by the Company pursuant
to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date of
this Registration Statement and prior to the filing of a post-effective
amendment which indicates that all securities offered hereby have been sold or
which deregisters all securities then remaining unsold, shall be deemed to be
incorporated by reference in this registration statement and to be a part hereof
from the date of filing of such documents. Any statement contained in a document
incorporated or deemed to be incorporated by reference in this registration
statement shall be deemed to be modified or superseded for purposes of this
registration statement to the extent that a statement contained herein or in any
other subsequently filed document which also is or is deemed to be incorporated
by reference herein modifies or supersedes such statement. Any such statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this registration statement.

ITEM 4.  DESCRIPTION OF SECURITIES.

         This item is not applicable.

                                      II-1
4
ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         This item is not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the Delaware General Corporation Law ("Delaware Law")
provides that a corporation may indemnify a director, officer, employee or
agent made a party to an action by reason of the fact that he was a director,
officer, employee or agent of the corporation, or was serving at the request of
the corporation, against expenses actually and reasonably incurred, including
attorneys' fees, in connection with such action, if he acted in good faith and
in a manner he reasonably believed to be in, or not opposed to, the best
interests of the corporation and, with respect to any criminal action, had no
reasonable cause to believe his conduct was unlawful.

         The Company's Certificate of Incorporation limits, to the maximum
extent permitted by Delaware Law, the personal liability of a director to the
Company or its shareholders for monetary damages for breach of fiduciary duty
as a director. The Company's By-laws provide that the Company shall indemnify
its officers and directors to the fullest extent permitted by Delaware Law
against all expense, liability and loss, including attorney's fees, actually
and reasonably incurred and may purchase and maintain insurance against any
liability asserted and incurred by reason of serving as such, whether or not the
Company has the power to indemnify against such liability. The Company has
entered into indemnification agreements with its officers and directors
containing provisions which are in some respects broader than the specific
indemnification provisions contained in Delaware Law and which require that, to
the extent the Company maintains liability insurance applicable to officers or
directors, each officer and director shall be covered by such policies to the
same extent as are accorded the most favorably insured of the Company's
officers or directors, as the case may be.

         Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers or persons controlling
the Company pursuant to the foregoing provisions and agreements, the Company
has been informed that in the opinion of the staff of the Commission such
indemnification is against public policy as expressed in the Securities Act
and is therefore unenforceable.
  
ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         This item is not applicable.

                                      II-2
5
ITEM 8.  EXHIBITS.

         The following exhibits are filed as part of this Registration Statement
or incorporated by reference herein:
Exhibit Number                      Description of Exhibits
- --------------                      -----------------------
4.1(a)            Restated Certificate of Incorporation of the Company (filed as Exhibit 3.1
                           to the Company's Annual Report on Form 10-K (File No. 0-15144) for the year
                           ended September 30, 1995 and incorporated herein by reference).

         4.1(b)*           Amendment dated June 19, 1995 to Restated Certificate of Incorporation of the
                           Company.

         4.1(c)*           Amendment dated March 18, 1996 to Restated Certificate of Incorporation of the
                           Company.

         4.2*              Amended By-laws of the Company, as of April 24, 1997.

         4.3               Form of certificate for the Company's common stock  (filed as Exhibit 4.2 to
                           the Company's Registration Statement on Form S-1 (File No. 33-67576) and 
                           incorporated herein by reference).

         4.4               Gartner Group, Inc. 1996 Long Term Stock Option Plan, as amended and restated on 
                           February 24, 1997 (filed as Exhibit 10.16 to the Company's Form 10-Q for the 
                           quarter ended June 30, 1997 (File No. 0-15144) and incorporated herein by
                           reference).

         5.1*              Opinion of Shipman & Goodwin LLP.

         23.1*             Independent Auditors' Consent, KPMG Peat Marwick LLP.

         23.2*             Consent of Independent Accountants, Price Waterhouse LLP
                           
         23.3*             Consent of Shipman & Goodwin LLP (included in Exhibit 5).

         24.1*             Powers of Attorney.
- -------------
* Filed herewith.

                                      II-3
6
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
         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.

                  (2) 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 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, each filing of the
registrant's annual report pursuant to Section 13(a) or 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
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 of 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-4
7
                                   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 Stamford and State of Connecticut on the 8th
day of September, 1997.

                                      GARTNER GROUP, INC.

                                      BY  /s/   MANUEL A. FERNANDEZ*
                                        --------------------------------------
                                           MANUEL A. FERNANDEZ
                                           CHAIRMAN, PRESIDENT
                                               AND CHIEF EXECUTIVE OFFICER

         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 date indicated.
SIGNATURE                               TITLE                           DATE
           ---------                               -----                           ----
/s/Manuel A. Fernandez*             Chairman, President and Chief           September 8, 1997
- -------------------------------         Executive Officer (principal
       MANUEL A. FERNANDEZ                   executive officer)

    /s/John F. Halligan*               Executive Vice President, Chief          September 8, 1997
- ------------------------------         Financial Officer and Secretary
       JOHN F. HALLIGAN                   (principal financial and
                                              accounting officer)

    /s/William O. Grabe*                           Director                     September 8, 1997
- ------------------------------
       WILLIAM O. GRABE

   /s/Max D. Hopper*                               Director                     September 8, 1997
- ------------------------------
      MAX D. HOPPER

   /s/John P. Imlay, Jr.*                          Director                     September 8, 1997
- ------------------------------
      JOHN P. IMLAY, JR.

  /s/Stephen G. Pagliuca*                          Director                     September 8, 1997
- ------------------------------
     STEPHEN G. PAGLIUCA
II-5
8
Director                    
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      DENNIS G. SISCO

   /s/ Robert E. Weissman*                         Director                     September 8, 1997
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       ROBERT E. WEISSMAN

*By:   /s/ John F. Halligan                                                     September 8, 1997
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       JOHN F. HALLIGAN
       ATTORNEY-IN-FACT
II-6
9
                                  EXHIBIT INDEX
Exhibit Number                      Description of Exhibits                             Sequentially
- --------------                      -----------------------                             Numbered Page
                                                                                        -------------
4.1(a)            Restated Certificate of Incorporation of the Company
                           (filed as Exhibit 3.1 to the Company's Annual Report
                           on Form 10-K (File No. 0-15144) for the year ended
                           September 30, 1995 and incorporated herein by
                           reference).

         4.1(b)*           Amendment dated June 19, 1995 to Restated Certificate
                           of Incorporation of the Company.
 .
         4.1(c)*           Amendment dated March 18, 1996 to Restated
                           Certificate of Incorporation of the Company.

         4.2*              Amended By-laws of the Company, as of April 24, 1997.

         4.3               Form of certificate for the Company's common stock
                           (filed as Exhibit 4.2 to the Company's Registration
                           Statement on Form S-1 (File No. 33-67576) and
                           incorporated herein by reference).

         4.4               Gartner Group, Inc. 1996 Long Term Stock Option Plan,
                           as amended and restated on February 24, 1997
                           (filed as Exhibit 10.16 to the Company's Form 10-Q
                           for the quarter ended June 30, 1997 (File No.
                           0-15144) and incorporated herein by reference).

         5.1*              Opinion of Shipman & Goodwin LLP.

         23.1*             Independent Auditors' Consent, KPMG Peat
                           Marwick LLP.

         23.2*             Consent of Independent Accountants, Price
                           Waterhouse LLP.

         23.3*             Consent of Shipman & Goodwin LLP (included in
                           Exhibit 5).

         24.1*             Powers of Attorney.
- -------------
* Filed herewith.