<PAGE>   1
   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON SEPTEMBER 15, 2000.

                         REGISTRATION NO. _____________

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

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

            DELAWARE                                      36-2815480
 (State or other jurisdiction of                       (I.R.S. Employer
  incorporation or organization)                     Identification Number)

                 233 SOUTH WACKER DRIVE, CHICAGO, ILLINOIS 60606
                                 (312) 651-3000
    (Address, including zip code, and telephone number, including area code,
                  of registrant's principal executive offices)

                                 EDWARD HAMBURG
    EXECUTIVE VICE PRESIDENT, CORPORATE OPERATIONS, CHIEF FINANCIAL OFFICER,
                                 AND SECRETARY
                                    SPSS INC.
                             233 SOUTH WACKER DRIVE
                             CHICAGO, ILLINOIS 60606
                                 (312) 651-3000
 (Name, address, including zip code, and telephone number, including area code,
                              of agent for service)

                                   Copies to:

                            LAWRENCE R. SAMUELS, ESQ.
                                 ROSS & HARDIES
                             150 N. MICHIGAN AVENUE
                             CHICAGO, ILLINOIS 60601
                                 (312) 558-1000

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
==========================================================================================================================
                                                              Proposed               457(h)
                                        Amount                maximum               Proposed               Amount of
           Title of                     to be              offering price          aggregate             registration
  Securities to be registered        registered(1)           per share(2)       offering price(3)              fee
--------------------------------------------------------------------------------------------------------------------------
<S>                                    <C>                    <C>                 <C>                      <C>
Common Stock, $.01 par value           626,000                $25.281             $15,825,906              $4,178.04
==========================================================================================================================
</TABLE>

(1)   The securities being registered include a maximum of 626,000 shares
      issuable upon the exercise of options under the 1999 Employee Equity
      Incentive Plan assuming full participation of employees under that plan.

(2)   Solely for the purpose of calculating the registration fee, the offering
      price per share, the aggregate offering price and the amount of the
      registration fee have been computed in accordance with Rule 457(c) under
      the Securities Act of 1933, as amended. Accordingly, the price per share
      of common stock has been calculated to be equal to the average of the high
      and low prices for a share of common stock as reported by the Nasdaq
      National Market on September 13, 2000, which is a specified date within
      five business days prior to the original date of filing of this
      Registration Statement.

(3)   Solely for the purpose of calculating the registration fee, the proposed
      aggregate offering price has been estimated in accordance with Rule 457(h)
      promulgated under the Securities Act. Accordingly, the aggregate offering
      price and the fee have been computed based on the prices at which the
      options may be exercised.

================================================================================

<PAGE>   2
                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

Item 1.       Plan Information

      The documents containing the information specified in Part I of this
Registration Statement will be sent or given to employees as specified by Rule
428(b)(1) of the Securities Act of 1933, as amended (the "Securities Act"). Such
documents are not required to be and are not filed with the Securities and
Exchange Commission (the "SEC" or the "Commission") either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to
Rule 424. These documents and the documents incorporated by reference in this
Registration Statement pursuant to Item 3 of Part II of this Form S-8, taken
together, constitute a prospectus that meets the requirements of Section 10(a)
of the Securities Act.

Item 2.       Registrant Information and Employee Plan Annual Information.

      Upon written or oral request, any of the documents incorporated by
reference in Item 3 of Part II of this Registration Statement (which documents
are incorporated by reference in this Section 10(a) Prospectus), other documents
required to be delivered to eligible employees pursuant to Rule 428(b) or
additional information about the SPSS Inc. 1999 Employee Equity Incentive Plan
and its administrators are available without charge by contacting:

                                 Edward Hamburg
                 Executive Vice President, Corporate Operations,
                      Chief Financial Officer and Secretary
                       233 South Wacker Drive, 11th Floor
                            Telephone: (312) 651-3000

                                     PART II

              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.       Incorporation of Certain Documents by Reference

      The SEC allows us to incorporate by reference the information that we file
with the SEC, which means that we can disclose important information to you by
referring you to those documents. The information incorporated by reference is
considered part of this prospectus, and information that we file later with the
SEC will automatically update and supersede this information. We incorporate by
reference the documents listed below and any future filings we make with the SEC
under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934.

      SPSS hereby incorporates by reference the following documents previously
filed with the Commission:

              (a)   Our annual report on Form 10-K, filed March 30, 2000 for the
      fiscal year ended December 31, 1999;

              (b)   Our quarterly report on Form 10-Q, filed May 15, 2000 for
      the fiscal quarter ended March 31, 2000;



<PAGE>   3
              (c)   Our quarterly report on form 10-Q, filed August 14, 2000 for
      the fiscal quarter ended June 30, 2000;

              (d)   Our current report on Form 8-K and amendments thereto filed
      with the Commission on June 30, 2000 (Norusis litigation);

              (e)   The description of our common stock contained in our
      registration statement on Form 8-A filed with the SEC on August 4, 1993,
      pursuant to Section 12 of the Exchange Act; and

              (f)   Our proxy statement, filed with the SEC on May 15, 2000, for
      its annual meeting of stockholders held on June 14, 2000, except for the
      compensation committee report contained therein.

              With respect to the unaudited interim financial information for
the periods ended March 31, 1999 and 2000 and June 30, 1999 and 2000,
incorporated by reference herein, the independent certified public accountants
have reported that they applied limited procedures in accordance with
professional standards for a review of such information. However, their separate
reports included in SPSS' quarterly reports on Form 10-Q for the quarters ended
March 31, 2000 and June 30, 2000, and incorporated by reference herein, state
that they did not audit and they do not express an opinion on that interim
financial information. Accordingly, the degree of reliance on their report on
such information should be restricted in light of the limited nature of the
review procedures applied. The accountants are not subject to the liability
provisions of section 11 of the Securities Act of 1933 for their report on the
unaudited interim financial information because the report is not a "report" or
a "part" of the registration statement prepared or certified by the accountants
within the meaning of sections 7 and 11 of the Securities Act.

Item 4.       Description of Securities

                    Not applicable.

Item 5.       Interests of Named Experts and Counsel

                    Not applicable.

Item 6.       Indemnification of Officers and Directors

      SPSS' Certificate of Incorporation provides for indemnification to the
full extent permitted by the laws of the State of Delaware against and with
respect to threatened, pending or completed actions, suits or proceedings
arising from or alleged to arise from, a party's actions or omissions as a
director, officer, employee or agent of SPSS or of any other corporation,
partnership, joint venture, trust or other enterprise which has served in such
capacity at the request of SPSS if the acts or omissions occurred, or were or
are alleged to have occurred, while said party was a director or officer of
SPSS; provided, however, SPSS shall not indemnify any director or officer in an
action against SPSS unless SPSS shall have consented to the action. Generally,
under Delaware law, indemnification will only be available where an officer or
director can establish that he/she acted in good faith and in a manner which was
reasonably believed to be in or not opposed to the best interests of SPSS.

      Section 145 of the Delaware General Corporation Law provides that a
corporation may indemnify a director, officer, employee or agent made a party to
an action by reason of the fact


<PAGE>   4
that the person was a director, officer, employee or agent of the corporation or
was serving at the request of the corporation, against expenses actually
incurred by the person in connection with the action if the person acted in good
faith and in a manner such person reasonably believed to be in, or not opposed
to, the best interest of the corporation with respect to any criminal action,
and had no reasonable cause to believe his conduct was unlawful. Delaware law
does not permit a corporation to eliminate a director's duty of care, and the
provisions of SPSS' Certificate of Incorporation have no effect on the
availability of equitable remedies such as injunction or rescission, based upon
a director's breach of the duty of care.

      SPSS maintains a director's and officer's liability insurance policy which
indemnifies directors and officers for specified losses arising from a claim by
reason of a wrongful act, as defined, under certain circumstances where SPSS
does not provide indemnification.

      Under the applicable provisions of the Delaware General Corporation Law,
any indemnification described above shall be made by the corporation only as
authorized in the specific case upon a determination that the indemnification of
the director, officer, employee or agent is proper in the circumstances because
he or she has met the applicable standard of conduct. Such determination shall
be made:

              (1)   By the Board of Directors by a majority vote of a quorum
      consisting of directors who are not parties to such action, suit or
      proceeding; or

              (2)   If such a quorum is not obtainable or, even if obtainable, a
      quorum of disinterested directors so directs, by independent legal counsel
      in a written opinion; or

              (3)   By the affirmative vote of a majority of the shares entitled
      to vote thereon.

Item 7.       Exemption from Registration Claimed.

                    Not applicable.

Item 8.       Exhibits.

  Exhibit                                                          Incorporation
   Number     Description                                          by Reference
 ---------    -----------                                          -------------

    4.1       SPSS Inc. 1999 Employee Equity Incentive Plan

    5.1       Opinion of Ross & Hardies regarding legality of
              shares of Common Stock.

   15.1       Letter Re: Unaudited Interim Financial
              Information.

   23.1       Consent of KPMG LLP.

   23.2       Consent of Ross & Hardies (contained in opinion
              filed as Exhibit 5.1).

   24.1       Power of Attorney.                                          *


-----------------------------

*     Power of attorney is contained within the signature page.


  Item 9.     Undertakings.
  ------      ------------

     The undersigned registrant hereby undertakes:



                                       -3-
<PAGE>   5
              (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;

              (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 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.

              (iii) To include any material information with respect to the plan
      of distribution not previously disclosed in this 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.

      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.

      Insofar as indemnification for 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.




                                      -4-
<PAGE>   6
                                   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 Chicago, State of Illinois, on September 13,
2000.

                                     SPSS Inc.

                                     By: /s/ Jack Noonan
                                         ---------------------------------------
                                         Jack Noonan
                                         President and Chief Executive Officer


                                POWER OF ATTORNEY

              Each person whose signature appears below hereby constitutes
and appoints Jack Noonan and Edward Hamburg, and each of them, the true and
lawful attorneys-in-fact and agents of the undersigned, with full power of
substitution and resubstitution, for and in the name, place and stead of the
undersigned, in any and all capacities, to sign any and all amendments
(including post-effective amendments) to this Registration Statement, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, and hereby grants to
such attorneys-in-fact and agents, and each of them, full power and authority to
do and perform each and every act and thing requisite and necessary to be done
in furtherance of the foregoing, as fully to all intents and purposes as the
undersigned might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact and agents, or any of them, or their or his
substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

              Pursuant to the requirements of the Securities Act of 1933,
this Registration Statement has been signed by the following persons in the
capacities indicated on September 13, 2000.

Signature                                                Title(s)
---------                                                --------

/s/ Norman H. Nie                         Chairman of the Board
-------------------------------
Norman H. Nie

/s/ Jack Noonan                           President, Chief Executive Officer and
-------------------------------             Director
Jack Noonan

/s/ Edward Hamburg                        Executive Vice President, Corporate
--------------------------------            Operations, Chief Financial Officer
Edward Hamburg                              and Secretary

/s/ Robert Brinkmann                      Controller and Assistant Secretary
-------------------------------
Robert Brinkmann

/s/ Michael Blair                         Director
-------------------------------
Michael Blair

/s/ Bernard Goldstein                     Director
-------------------------------
Bernard Goldstein

/s/ Merritt Lutz                          Director
-------------------------------
Merritt Lutz


<PAGE>   7
                                    SPSS INC.

                                  EXHIBIT INDEX

                                                                   Location Of
                                                                   Document in
                                                                    Sequential
Exhibit                                                             Numbering
   No.        Description                                             System
-------       -----------                                          -----------

  4.1         SPSS Inc. 1999 Employee Equity Incentive Plan

  5.1         Opinion of Ross & Hardies regarding legality of
              shares of Common Stock.

 15.1         Letter Re:  Unaudited Financial Information

 23.1         Consent of KPMG LLP.

 23.2         Consent of Ross & Hardies (contained in opinion
              filed as Exhibit 5.1).

 24.1         Power of Attorney.*



              * Power of attorney is contained within the signature page.
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{"company-data": {"conformed-name": "SPSS INC", "cik": "0000869570", "assigned-sic": "7372", "irs-number": "362815480", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-45900", "film-number": "723954"}, "business-address": {"street1": "233 SOUTH WACKER DRIVE", "city": "CHICAGO", "state": "IL", "zip": "60606", "phone": "3123292400"}, "mail-address": {"street1": "233 SOUTH WACKER DRIVE", "city": "CHICAGO", "state": "IL", "zip": "60606"}}
1
   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON SEPTEMBER 15, 2000.

                         REGISTRATION NO. _____________

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

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

            DELAWARE                                      36-2815480
 (State or other jurisdiction of                       (I.R.S. Employer
  incorporation or organization)                     Identification Number)

                 233 SOUTH WACKER DRIVE, CHICAGO, ILLINOIS 60606
                                 (312) 651-3000
    (Address, including zip code, and telephone number, including area code,
                  of registrant's principal executive offices)

                                 EDWARD HAMBURG
    EXECUTIVE VICE PRESIDENT, CORPORATE OPERATIONS, CHIEF FINANCIAL OFFICER,
                                 AND SECRETARY
                                    SPSS INC.
                             233 SOUTH WACKER DRIVE
                             CHICAGO, ILLINOIS 60606
                                 (312) 651-3000
 (Name, address, including zip code, and telephone number, including area code,
                              of agent for service)

                                   Copies to:

                            LAWRENCE R. SAMUELS, ESQ.
                                 ROSS & HARDIES
                             150 N. MICHIGAN AVENUE
                             CHICAGO, ILLINOIS 60601
                                 (312) 558-1000

                         CALCULATION OF REGISTRATION FEE
==========================================================================================================================
                                                              Proposed               457(h)
                                        Amount                maximum               Proposed               Amount of
           Title of                     to be              offering price          aggregate             registration
  Securities to be registered        registered(1)           per share(2)       offering price(3)              fee
--------------------------------------------------------------------------------------------------------------------------
Common Stock, $.01 par value           626,000                $25.281             $15,825,906              $4,178.04
==========================================================================================================================
(1)   The securities being registered include a maximum of 626,000 shares
      issuable upon the exercise of options under the 1999 Employee Equity
      Incentive Plan assuming full participation of employees under that plan.

(2)   Solely for the purpose of calculating the registration fee, the offering
      price per share, the aggregate offering price and the amount of the
      registration fee have been computed in accordance with Rule 457(c) under
      the Securities Act of 1933, as amended. Accordingly, the price per share
      of common stock has been calculated to be equal to the average of the high
      and low prices for a share of common stock as reported by the Nasdaq
      National Market on September 13, 2000, which is a specified date within
      five business days prior to the original date of filing of this
      Registration Statement.

(3)   Solely for the purpose of calculating the registration fee, the proposed
      aggregate offering price has been estimated in accordance with Rule 457(h)
      promulgated under the Securities Act. Accordingly, the aggregate offering
      price and the fee have been computed based on the prices at which the
      options may be exercised.

================================================================================
2
                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

Item 1.       Plan Information

      The documents containing the information specified in Part I of this
Registration Statement will be sent or given to employees as specified by Rule
428(b)(1) of the Securities Act of 1933, as amended (the "Securities Act"). Such
documents are not required to be and are not filed with the Securities and
Exchange Commission (the "SEC" or the "Commission") either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to
Rule 424. These documents and the documents incorporated by reference in this
Registration Statement pursuant to Item 3 of Part II of this Form S-8, taken
together, constitute a prospectus that meets the requirements of Section 10(a)
of the Securities Act.

Item 2.       Registrant Information and Employee Plan Annual Information.

      Upon written or oral request, any of the documents incorporated by
reference in Item 3 of Part II of this Registration Statement (which documents
are incorporated by reference in this Section 10(a) Prospectus), other documents
required to be delivered to eligible employees pursuant to Rule 428(b) or
additional information about the SPSS Inc. 1999 Employee Equity Incentive Plan
and its administrators are available without charge by contacting:

                                 Edward Hamburg
                 Executive Vice President, Corporate Operations,
                      Chief Financial Officer and Secretary
                       233 South Wacker Drive, 11th Floor
                            Telephone: (312) 651-3000

                                     PART II

              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.       Incorporation of Certain Documents by Reference

      The SEC allows us to incorporate by reference the information that we file
with the SEC, which means that we can disclose important information to you by
referring you to those documents. The information incorporated by reference is
considered part of this prospectus, and information that we file later with the
SEC will automatically update and supersede this information. We incorporate by
reference the documents listed below and any future filings we make with the SEC
under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934.

      SPSS hereby incorporates by reference the following documents previously
filed with the Commission:

              (a)   Our annual report on Form 10-K, filed March 30, 2000 for the
      fiscal year ended December 31, 1999;

              (b)   Our quarterly report on Form 10-Q, filed May 15, 2000 for
      the fiscal quarter ended March 31, 2000;
3
              (c)   Our quarterly report on form 10-Q, filed August 14, 2000 for
      the fiscal quarter ended June 30, 2000;

              (d)   Our current report on Form 8-K and amendments thereto filed
      with the Commission on June 30, 2000 (Norusis litigation);

              (e)   The description of our common stock contained in our
      registration statement on Form 8-A filed with the SEC on August 4, 1993,
      pursuant to Section 12 of the Exchange Act; and

              (f)   Our proxy statement, filed with the SEC on May 15, 2000, for
      its annual meeting of stockholders held on June 14, 2000, except for the
      compensation committee report contained therein.

              With respect to the unaudited interim financial information for
the periods ended March 31, 1999 and 2000 and June 30, 1999 and 2000,
incorporated by reference herein, the independent certified public accountants
have reported that they applied limited procedures in accordance with
professional standards for a review of such information. However, their separate
reports included in SPSS' quarterly reports on Form 10-Q for the quarters ended
March 31, 2000 and June 30, 2000, and incorporated by reference herein, state
that they did not audit and they do not express an opinion on that interim
financial information. Accordingly, the degree of reliance on their report on
such information should be restricted in light of the limited nature of the
review procedures applied. The accountants are not subject to the liability
provisions of section 11 of the Securities Act of 1933 for their report on the
unaudited interim financial information because the report is not a "report" or
a "part" of the registration statement prepared or certified by the accountants
within the meaning of sections 7 and 11 of the Securities Act.

Item 4.       Description of Securities

                    Not applicable.

Item 5.       Interests of Named Experts and Counsel

                    Not applicable.

Item 6.       Indemnification of Officers and Directors

      SPSS' Certificate of Incorporation provides for indemnification to the
full extent permitted by the laws of the State of Delaware against and with
respect to threatened, pending or completed actions, suits or proceedings
arising from or alleged to arise from, a party's actions or omissions as a
director, officer, employee or agent of SPSS or of any other corporation,
partnership, joint venture, trust or other enterprise which has served in such
capacity at the request of SPSS if the acts or omissions occurred, or were or
are alleged to have occurred, while said party was a director or officer of
SPSS; provided, however, SPSS shall not indemnify any director or officer in an
action against SPSS unless SPSS shall have consented to the action. Generally,
under Delaware law, indemnification will only be available where an officer or
director can establish that he/she acted in good faith and in a manner which was
reasonably believed to be in or not opposed to the best interests of SPSS.

      Section 145 of the Delaware General Corporation Law provides that a
corporation may indemnify a director, officer, employee or agent made a party to
an action by reason of the fact
4
that the person was a director, officer, employee or agent of the corporation or
was serving at the request of the corporation, against expenses actually
incurred by the person in connection with the action if the person acted in good
faith and in a manner such person reasonably believed to be in, or not opposed
to, the best interest of the corporation with respect to any criminal action,
and had no reasonable cause to believe his conduct was unlawful. Delaware law
does not permit a corporation to eliminate a director's duty of care, and the
provisions of SPSS' Certificate of Incorporation have no effect on the
availability of equitable remedies such as injunction or rescission, based upon
a director's breach of the duty of care.

      SPSS maintains a director's and officer's liability insurance policy which
indemnifies directors and officers for specified losses arising from a claim by
reason of a wrongful act, as defined, under certain circumstances where SPSS
does not provide indemnification.

      Under the applicable provisions of the Delaware General Corporation Law,
any indemnification described above shall be made by the corporation only as
authorized in the specific case upon a determination that the indemnification of
the director, officer, employee or agent is proper in the circumstances because
he or she has met the applicable standard of conduct. Such determination shall
be made:

              (1)   By the Board of Directors by a majority vote of a quorum
      consisting of directors who are not parties to such action, suit or
      proceeding; or

              (2)   If such a quorum is not obtainable or, even if obtainable, a
      quorum of disinterested directors so directs, by independent legal counsel
      in a written opinion; or

              (3)   By the affirmative vote of a majority of the shares entitled
      to vote thereon.

Item 7.       Exemption from Registration Claimed.

                    Not applicable.

Item 8.       Exhibits.

  Exhibit                                                          Incorporation
   Number     Description                                          by Reference
 ---------    -----------                                          -------------

    4.1       SPSS Inc. 1999 Employee Equity Incentive Plan

    5.1       Opinion of Ross & Hardies regarding legality of
              shares of Common Stock.

   15.1       Letter Re: Unaudited Interim Financial
              Information.

   23.1       Consent of KPMG LLP.

   23.2       Consent of Ross & Hardies (contained in opinion
              filed as Exhibit 5.1).

   24.1       Power of Attorney.                                          *

-----------------------------

*     Power of attorney is contained within the signature page.

  Item 9.     Undertakings.
  ------      ------------

     The undersigned registrant hereby undertakes:

                                       -3-
5
              (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;

              (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 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.

              (iii) To include any material information with respect to the plan
      of distribution not previously disclosed in this 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.

      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.

      Insofar as indemnification for 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.

                                      -4-
6
                                   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 Chicago, State of Illinois, on September 13,
2000.

                                     SPSS Inc.

                                     By: /s/ Jack Noonan
                                         ---------------------------------------
                                         Jack Noonan
                                         President and Chief Executive Officer

                                POWER OF ATTORNEY

              Each person whose signature appears below hereby constitutes
and appoints Jack Noonan and Edward Hamburg, and each of them, the true and
lawful attorneys-in-fact and agents of the undersigned, with full power of
substitution and resubstitution, for and in the name, place and stead of the
undersigned, in any and all capacities, to sign any and all amendments
(including post-effective amendments) to this Registration Statement, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, and hereby grants to
such attorneys-in-fact and agents, and each of them, full power and authority to
do and perform each and every act and thing requisite and necessary to be done
in furtherance of the foregoing, as fully to all intents and purposes as the
undersigned might or could do in person, hereby ratifying and confirming all
that said attorneys-in-fact and agents, or any of them, or their or his
substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

              Pursuant to the requirements of the Securities Act of 1933,
this Registration Statement has been signed by the following persons in the
capacities indicated on September 13, 2000.

Signature                                                Title(s)
---------                                                --------

/s/ Norman H. Nie                         Chairman of the Board
-------------------------------
Norman H. Nie

/s/ Jack Noonan                           President, Chief Executive Officer and
-------------------------------             Director
Jack Noonan

/s/ Edward Hamburg                        Executive Vice President, Corporate
--------------------------------            Operations, Chief Financial Officer
Edward Hamburg                              and Secretary

/s/ Robert Brinkmann                      Controller and Assistant Secretary
-------------------------------
Robert Brinkmann

/s/ Michael Blair                         Director
-------------------------------
Michael Blair

/s/ Bernard Goldstein                     Director
-------------------------------
Bernard Goldstein

/s/ Merritt Lutz                          Director
-------------------------------
Merritt Lutz
7
                                    SPSS INC.

                                  EXHIBIT INDEX

                                                                   Location Of
                                                                   Document in
                                                                    Sequential
Exhibit                                                             Numbering
   No.        Description                                             System
-------       -----------                                          -----------

  4.1         SPSS Inc. 1999 Employee Equity Incentive Plan

  5.1         Opinion of Ross & Hardies regarding legality of
              shares of Common Stock.

 15.1         Letter Re:  Unaudited Financial Information

 23.1         Consent of KPMG LLP.

 23.2         Consent of Ross & Hardies (contained in opinion
              filed as Exhibit 5.1).

 24.1         Power of Attorney.*

              * Power of attorney is contained within the signature page.