<PAGE>   1

    As filed with the Securities and Exchange Commission on October 8, 1999
                                                 Registration No. 333-__________
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

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

                                  CLARIFY INC.
             (Exact name of Registrant as specified in its charter)

           DELAWARE                                     77-0259235
   (State of incorporation)             (I.R.S. Employer Identification No.)


                              2560 Orchard Parkway
                           San Jose, California 95131
                    (Address of principal executive offices)

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

               1999 NON-EXECUTIVE STOCK OPTION/STOCK ISSUANCE PLAN
                 OPTIONS ASSUMED IN CONNECTION WITH ACQUISITION
                            (Full title of the Plans)

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

                                 ANTHONY ZINGALE
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                                  CLARIFY INC.
                              2560 ORCHARD PARKWAY
                           SAN JOSE, CALIFORNIA 95131
                                 (408) 965-7000
 (Name, address and telephone number, including area code, of agent for service)

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

                                    Copy to:

                                 Elias J. Blawie
                                Venture Law Group
                           A Professional Corporation
                               2800 Sand Hill Road
                          Menlo Park, California 94025
                                 (650) 854-4488

                                Page 1 of 8 Pages
                             Exhibit Index on Page 8
               (Calculation of Registration Fee on following page)

<PAGE>   2

<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
                                                  CALCULATION OF REGISTRATION FEE
-----------------------------------------------------------------------------------------------------------------------------------
                                                              Proposed           Proposed
                                                              Maximum             Maximum            Maximum            Amount of
                                                           Amount to be        Offering Price       Aggregate         Registration
 Title of Securities to be Registered                      Registered(1)         Per Share        Offering Price          Fee
-----------------------------------------------------------------------------------------------------------------------------------
<S>                                                        <C>                 <C>                <C>                 <C>
1999 NON-EXECUTIVE STOCK OPTION/STOCK ISSUANCE PLAN
  Common Stock,
  $0.0001 par value ...............................        300,000 Shares        $ 45.1875(2)       $13,556,250        $3,768.64

OPTIONS ASSUMED IN CONNECTION WITH ACQUISITION (3)
  Common Stock,
  $0.0001 par value ...............................         60,207 Shares        $  9.5122(4)       $   572,701        $  159.21


  Total ...........................................        360,207 Shares        $ 45.1875 -        $14,128,951        $3,927.85
                                                                                    9.5122
</TABLE>

----------

(1)     This Registration Statement shall also cover any additional shares of
        Common Stock which become issuable under any of the Plans being
        registered pursuant to this Registration Statement by reason of any
        stock dividend, stock split, recapitalization or any other similar
        transaction effected without the receipt of consideration which results
        in an increase in the number of the Registrant's outstanding shares of
        Common Stock.

(2)     Estimated in accordance with Rule 457(h) under the Securities Act of
        1933 (the "Securities Act") solely for the purpose of calculating the
        registration fee. The computation is based upon the average of the high
        and low sale prices of the Common Stock as reported on The Nasdaq Stock
        Market on September 20, 1999, multiplied by 85%, which is the percentage
        of the trading purchase price applicable to purchases under the
        referenced Plan.

(3)     Options assumed in connection with the acquisition of Newtonian
        Software, Inc., a North Carolina corporation ("Newtonian"), by Clarify
        Inc., a Delaware corporation (the "Company"), pursuant to the Stock
        Purchase Agreement and Plan of Reorganization dated August 17, 1999 by
        and among Newtonian, the Company, Clarify Acquisition Corporation, a
        Delaware corporation and wholly owned subsidiary of the Company, and
        Tarquin Limited (the "Acquisition").

(4)     Computed in accordance with Rule 457(h) under the Securities Act solely
        for the purpose of calculating the registration fee. Computation based
        on the weighted average exercise price of the Common Stock issuable
        pursuant to the options assumed in the Acquisition.

<PAGE>   3

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.        INCORPORATION OF DOCUMENTS BY REFERENCE.

        The following documents filed with the Securities and Exchange
Commission (the "Commission") are hereby incorporated by reference:

        (a)    The Registrant's report on Form 10-K for the fiscal year ended
December 31, 1998.

        (b)    The Registrant's quarterly report on Form 10-Q for the fiscal
quarter ended March 31, 1999.

        (c)    The description of the Registrant's Common Stock contained in the
Registrant's Registration Statement on Form 8-A filed with the Commission under
Section 12 of the Securities Exchange Act of 1934 (the "Exchange Act") on
September 15, 1995, including any amendment or report filed for the purpose of
updating such description.

        All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, 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
part hereof from the date of filing such documents.

Item 4.        DESCRIPTION OF SECURITIES.  Not applicable.

Item 5.        INTERESTS OF NAMED EXPERTS AND COUNSEL.  Not applicable.

Item 6.        INDEMNIFICATION OF DIRECTORS AND OFFICERS.

        The Registrant's Certificate of Incorporation reduces the liability of a
director to the corporation or its shareholders for monetary damages for
breaches of his or her fiduciary duty of care to the fullest extent permissible
under Delaware law. The Bylaws of the Registrant further provide for
indemnification of corporate agents to the maximum extent permitted by the
Delaware General Corporation Law. In addition, the Registrant has entered into
Indemnification Agreements with its officers and directors.

Item 7.        EXEMPTION FROM REGISTRATION CLAIMED.  Not applicable.

Item 8.        EXHIBITS.

<TABLE>
<CAPTION>
                Exhibit
                Number
                ------
<S>                         <C>
                5.1         Opinion of Venture Law Group, A Professional Corporation.
                23.1        Consent of Venture Law Group, A Professional Corporation
                            (included in Exhibit 5.1).
                23.2        Consent of Independent Accountants (see p. 7).
                24.1        Powers of Attorney (see p. 6).
</TABLE>

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



                                      -3-
<PAGE>   4

Item 9.        UNDERTAKINGS.

        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 purposes of determining any liability under the
Securities Act, 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, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act 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 the indemnification for liabilities arising under the
Securities Act 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 Commission such
indemnification is against public policy as expressed in the Securities 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 a successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered hereunder, the Registrant will, unless in the opinion of its counsel
the question has already been settled by controlling precedent, submit to a
court of appropriate jurisdiction the question of whether such indemnification
by it is against public policy as expressed in the Securities Act and will be
governed by the final adjudication of such issue.

                            [Signature Pages Follow]



                                      -4-
<PAGE>   5

                                   SIGNATURES


        Pursuant to the requirements of the Securities Act of 1933, the
Registrant, Clarify Inc., a corporation organized and existing under the laws of
the State of Delaware, 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 San Jose, State of California, on this 8th day
of October, 1999.

                                   Clarify Inc.


                                   By:  /s/ Anthony Zingale
                                        ----------------------------------------
                                        Anthony Zingale
                                        Chief Executive Officer



                                      -5-
<PAGE>   6

                                POWER OF ATTORNEY

        KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Anthony Zingale and Jan Praisner, jointly
and severally, his or her attorneys-in-fact and agents, each with the power of
substitution and resubstitution, for him or her and in his or her name, place or
stead, in any and all capacities, to sign any amendments to this Registration
Statement on Form S-8, and to file such amendments, together with exhibits and
other documents in connection therewith, with the Securities and Exchange
Commission, granting to each attorney-in-fact and agent, full power and
authority to do and perform each and every act and thing requisite and necessary
to be done in and about the premises, as fully as he or she might or could do in
person, and ratifying and confirming all that the attorney-in-facts and agents,
or his or her substitute or substitutes, may 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 and on the dates indicated.


<TABLE>
<CAPTION>
            Signature                             Title                                   Date
            ---------                             -----                                   ----
<S>                                <C>                                               <C>
/s/ Anthony Zingale                Chief Executive Officer and Director              October 8, 1999
-----------------------------        (Principal Executive Officer)
Anthony Zingale

/s/ Jan Praisner                   Chief Financial Officer (Principal Financial      October 8, 1999
-----------------------------        and Accounting Officer)
Jan Praisner

/s / David A. Stamm                Director                                          October 8, 1999
-----------------------------
David A. Stamm

/s/ Thomas H. Bredt                Director                                          October 8, 1999
-----------------------------
Thomas H. Bredt

/s/ Joseph B. Costello             Director                                          October 8, 1999
-----------------------------
Joseph B. Costello

/s/ Christopher H. Greendale       Director                                          October 8, 1999
-----------------------------
Christopher H. Greendale
</TABLE>



                                      -6-
<PAGE>   7

                       CONSENT OF INDEPENDENT ACCOUNTANTS

We hereby consent to the incorporation by reference in the Registration
Statement on Form S-8 of our report dated January 19, 1999 except for note 11
for which the date is March 12, 1999 relating to the consolidated financial
statements and our report dated January 19, 1999 relating to the consolidated
financial statement schedule of Clarify Inc., and subsidiaries which appears in
Clarify's Annual Report on Form 10-K for the year ended December 31, 1998.

/s/ PricewaterhouseCoopers LLP
------------------------------
PRICEWATERHOUSECOOPERS LLP


San Jose, California
October 8, 1999
<PAGE>   8

                                INDEX TO EXHIBITS


<TABLE>
<CAPTION>
  Exhibit
  Number
  ------
<S>          <C>

    5.1      Opinion of Venture Law Group, A Professional Corporation

   23.1      Consent of Venture Law Group, A Professional Corporation
             (included in Exhibit 5.1).

   23.2      Consent of Independent Accountants (see p. 7).

   24.1      Powers of Attorney (see p. 6).
</TABLE>
[{"type": "S-8", "sequence": "1", "description": "FORM 8", "secsgml_size_bytes": 15755}]
{"company-data": {"conformed-name": "CLARIFY INC", "cik": "0001000782", "assigned-sic": "7372", "irs-number": "770259235", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-88691", "film-number": "99725714"}, "business-address": {"street1": "2125 ONEL DRIVE", "city": "SAN JOSE", "state": "CA", "zip": "95134", "phone": "4089657000"}, "mail-address": {"street1": "2125 ONEL DRIVE", "city": "SAN JOSE", "state": "CA", "zip": "95131"}}
1

    As filed with the Securities and Exchange Commission on October 8, 1999
                                                 Registration No. 333-__________
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

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

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

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

                                  CLARIFY INC.
             (Exact name of Registrant as specified in its charter)

           DELAWARE                                     77-0259235
   (State of incorporation)             (I.R.S. Employer Identification No.)

                              2560 Orchard Parkway
                           San Jose, California 95131
                    (Address of principal executive offices)

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

               1999 NON-EXECUTIVE STOCK OPTION/STOCK ISSUANCE PLAN
                 OPTIONS ASSUMED IN CONNECTION WITH ACQUISITION
                            (Full title of the Plans)

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

                                 ANTHONY ZINGALE
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                                  CLARIFY INC.
                              2560 ORCHARD PARKWAY
                           SAN JOSE, CALIFORNIA 95131
                                 (408) 965-7000
 (Name, address and telephone number, including area code, of agent for service)

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

                                    Copy to:

                                 Elias J. Blawie
                                Venture Law Group
                           A Professional Corporation
                               2800 Sand Hill Road
                          Menlo Park, California 94025
                                 (650) 854-4488

                                Page 1 of 8 Pages
                             Exhibit Index on Page 8
               (Calculation of Registration Fee on following page)
2
-----------------------------------------------------------------------------------------------------------------------------------
                                                  CALCULATION OF REGISTRATION FEE
-----------------------------------------------------------------------------------------------------------------------------------
                                                              Proposed           Proposed
                                                              Maximum             Maximum            Maximum            Amount of
                                                           Amount to be        Offering Price       Aggregate         Registration
 Title of Securities to be Registered                      Registered(1)         Per Share        Offering Price          Fee
-----------------------------------------------------------------------------------------------------------------------------------
1999 NON-EXECUTIVE STOCK OPTION/STOCK ISSUANCE PLAN
  Common Stock,
  $0.0001 par value ...............................        300,000 Shares        $ 45.1875(2)       $13,556,250        $3,768.64

OPTIONS ASSUMED IN CONNECTION WITH ACQUISITION (3)
  Common Stock,
  $0.0001 par value ...............................         60,207 Shares        $  9.5122(4)       $   572,701        $  159.21

  Total ...........................................        360,207 Shares        $ 45.1875 -        $14,128,951        $3,927.85
                                                                                    9.5122
----------

(1)     This Registration Statement shall also cover any additional shares of
        Common Stock which become issuable under any of the Plans being
        registered pursuant to this Registration Statement by reason of any
        stock dividend, stock split, recapitalization or any other similar
        transaction effected without the receipt of consideration which results
        in an increase in the number of the Registrant's outstanding shares of
        Common Stock.

(2)     Estimated in accordance with Rule 457(h) under the Securities Act of
        1933 (the "Securities Act") solely for the purpose of calculating the
        registration fee. The computation is based upon the average of the high
        and low sale prices of the Common Stock as reported on The Nasdaq Stock
        Market on September 20, 1999, multiplied by 85%, which is the percentage
        of the trading purchase price applicable to purchases under the
        referenced Plan.

(3)     Options assumed in connection with the acquisition of Newtonian
        Software, Inc., a North Carolina corporation ("Newtonian"), by Clarify
        Inc., a Delaware corporation (the "Company"), pursuant to the Stock
        Purchase Agreement and Plan of Reorganization dated August 17, 1999 by
        and among Newtonian, the Company, Clarify Acquisition Corporation, a
        Delaware corporation and wholly owned subsidiary of the Company, and
        Tarquin Limited (the "Acquisition").

(4)     Computed in accordance with Rule 457(h) under the Securities Act solely
        for the purpose of calculating the registration fee. Computation based
        on the weighted average exercise price of the Common Stock issuable
        pursuant to the options assumed in the Acquisition.
3

                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.        INCORPORATION OF DOCUMENTS BY REFERENCE.

        The following documents filed with the Securities and Exchange
Commission (the "Commission") are hereby incorporated by reference:

        (a)    The Registrant's report on Form 10-K for the fiscal year ended
December 31, 1998.

        (b)    The Registrant's quarterly report on Form 10-Q for the fiscal
quarter ended March 31, 1999.

        (c)    The description of the Registrant's Common Stock contained in the
Registrant's Registration Statement on Form 8-A filed with the Commission under
Section 12 of the Securities Exchange Act of 1934 (the "Exchange Act") on
September 15, 1995, including any amendment or report filed for the purpose of
updating such description.

        All documents subsequently filed by the Registrant pursuant to Sections
13(a), 13(c), 14 and 15(d) of the Exchange Act, 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
part hereof from the date of filing such documents.

Item 4.        DESCRIPTION OF SECURITIES.  Not applicable.

Item 5.        INTERESTS OF NAMED EXPERTS AND COUNSEL.  Not applicable.

Item 6.        INDEMNIFICATION OF DIRECTORS AND OFFICERS.

        The Registrant's Certificate of Incorporation reduces the liability of a
director to the corporation or its shareholders for monetary damages for
breaches of his or her fiduciary duty of care to the fullest extent permissible
under Delaware law. The Bylaws of the Registrant further provide for
indemnification of corporate agents to the maximum extent permitted by the
Delaware General Corporation Law. In addition, the Registrant has entered into
Indemnification Agreements with its officers and directors.

Item 7.        EXEMPTION FROM REGISTRATION CLAIMED.  Not applicable.

Item 8.        EXHIBITS.
Exhibit
                Number
                ------
5.1         Opinion of Venture Law Group, A Professional Corporation.
                23.1        Consent of Venture Law Group, A Professional Corporation
                            (included in Exhibit 5.1).
                23.2        Consent of Independent Accountants (see p. 7).
                24.1        Powers of Attorney (see p. 6).
---------------

                                      -3-
4

Item 9.        UNDERTAKINGS.

        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 purposes of determining any liability under the
Securities Act, 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, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act 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 the indemnification for liabilities arising under the
Securities Act 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 Commission such
indemnification is against public policy as expressed in the Securities 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 a successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered hereunder, the Registrant will, unless in the opinion of its counsel
the question has already been settled by controlling precedent, submit to a
court of appropriate jurisdiction the question of whether such indemnification
by it is against public policy as expressed in the Securities Act and will be
governed by the final adjudication of such issue.

                            [Signature Pages Follow]

                                      -4-
5

                                   SIGNATURES

        Pursuant to the requirements of the Securities Act of 1933, the
Registrant, Clarify Inc., a corporation organized and existing under the laws of
the State of Delaware, 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 San Jose, State of California, on this 8th day
of October, 1999.

                                   Clarify Inc.

                                   By:  /s/ Anthony Zingale
                                        ----------------------------------------
                                        Anthony Zingale
                                        Chief Executive Officer

                                      -5-
6

                                POWER OF ATTORNEY

        KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Anthony Zingale and Jan Praisner, jointly
and severally, his or her attorneys-in-fact and agents, each with the power of
substitution and resubstitution, for him or her and in his or her name, place or
stead, in any and all capacities, to sign any amendments to this Registration
Statement on Form S-8, and to file such amendments, together with exhibits and
other documents in connection therewith, with the Securities and Exchange
Commission, granting to each attorney-in-fact and agent, full power and
authority to do and perform each and every act and thing requisite and necessary
to be done in and about the premises, as fully as he or she might or could do in
person, and ratifying and confirming all that the attorney-in-facts and agents,
or his or her substitute or substitutes, may 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 and on the dates indicated.
Signature                             Title                                   Date
            ---------                             -----                                   ----
/s/ Anthony Zingale                Chief Executive Officer and Director              October 8, 1999
-----------------------------        (Principal Executive Officer)
Anthony Zingale

/s/ Jan Praisner                   Chief Financial Officer (Principal Financial      October 8, 1999
-----------------------------        and Accounting Officer)
Jan Praisner

/s / David A. Stamm                Director                                          October 8, 1999
-----------------------------
David A. Stamm

/s/ Thomas H. Bredt                Director                                          October 8, 1999
-----------------------------
Thomas H. Bredt

/s/ Joseph B. Costello             Director                                          October 8, 1999
-----------------------------
Joseph B. Costello

/s/ Christopher H. Greendale       Director                                          October 8, 1999
-----------------------------
Christopher H. Greendale
-6-
7

                       CONSENT OF INDEPENDENT ACCOUNTANTS

We hereby consent to the incorporation by reference in the Registration
Statement on Form S-8 of our report dated January 19, 1999 except for note 11
for which the date is March 12, 1999 relating to the consolidated financial
statements and our report dated January 19, 1999 relating to the consolidated
financial statement schedule of Clarify Inc., and subsidiaries which appears in
Clarify's Annual Report on Form 10-K for the year ended December 31, 1998.

/s/ PricewaterhouseCoopers LLP
------------------------------
PRICEWATERHOUSECOOPERS LLP

San Jose, California
October 8, 1999
8

                                INDEX TO EXHIBITS
Exhibit
  Number
  ------
5.1      Opinion of Venture Law Group, A Professional Corporation

   23.1      Consent of Venture Law Group, A Professional Corporation
             (included in Exhibit 5.1).

   23.2      Consent of Independent Accountants (see p. 7).

   24.1      Powers of Attorney (see p. 6).