<PAGE>   1

       As filed with the Securities and Exchange Commission on November 22, 1999
                                                       Registration No. 333-____
================================================================================

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

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

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

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

                               QUINTUS CORPORATION
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                     <C>                               <C>
               DELAWARE                             7372                      77-0021612
     (State or other jurisdiction       (Primary Standard Industrial         (IRS Employer
   of incorporation or organization)     Classification Code Number)      Identification No.)
</TABLE>

                            47212 MISSION FALL COURT
                            FREMONT, CALIFORNIA 94539
               (Address of principal executive offices) (Zip Code)

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

                               QUINTUS CORPORATION
                             1995 STOCK OPTION PLAN
                                 1999 STOCK PLAN
                            1999 DIRECTOR OPTION PLAN
                           EMPLOYEE STOCK PURCHASE PLAN
                            1999 STOCK INCENTIVE PLAN
                            (Full title of the Plans)

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

                                 SUSAN SALVESEN
                             CHIEF FINANCIAL OFFICER
                               QUINTUS CORPORATION
                            47212 MISSION FALLS COURT
                            FREMONT, CALIFORNIA 94539
                     (Name and address of agent for service)
                                 (510) 624-2800
          (Telephone number, including area code, of agent for service)

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

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
========================================================================================================================
         Title of                                                    Proposed Maximum  Proposed Maximum
        Securities                                 Amount                Offering          Aggregate          Amount of
           to be                                   to be                   Price           Offering         Registration
        Registered                             Registered (1)          per Share (2)       Price (2)             Fee
        ----------                             --------------          -------------       ---------             ---
<S>                                           <C>                    <C>               <C>                  <C>
1995 Stock Option Plan(3)
    Options                                     2,215,242                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           2,215,242 shares         $    18.00         $39,874,356         $11,085.07

1999 Stock Incentive Plan(3)
    Options                                     1,000,000                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           1,000,000 shares         $    18.00         $18,000,000         $ 5,004.00

1999 Stock Plan
    Options                                       422,867                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           422,867 shares           $    18.00         $ 7,611,606         $ 2,116.03
</TABLE>



<PAGE>   2

<TABLE>
<S>                                           <C>                    <C>               <C>                  <C>
1999 Director Option Plan
    Options                                       500,000                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           500,000 shares           $    18.00         $ 9,000,000         $ 2,502.00

Employee Stock Purchase Plan
    Right to Purchase                           1,000,000                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           1,000,000 shares         $    18.00         $18,000,000         $ 5,004.00
</TABLE>


(1)     This Registration Statement shall also cover any additional shares of
        Common Stock which become issuable under the 1995 Stock Option Plan,
        1999 Stock Plan, 1999 Director Option Plan, Employee Stock Purchase
        Plan, and 1999 Stock Incentive Plan by reason of any stock dividend,
        stock split, recapitalization or other similar transaction effected
        without the receipt of consideration which results in an increase in the
        number of the outstanding shares of Common Stock of Quintus Corporation.

(2)     Calculated solely for purposes of this offering under Rule 457(h) of the
        Securities Act of 1933, as amended, on the basis of the fair market
        value per share of Common Stock of Quintus Corporation on November 15,
        1999.

(3)     The 2,215,242 shares reserved under the 1995 Stock Option Plan will
        become issuable under the 1999 Stock Incentive Plan if and to the extent
        that options outstanding under the 1995 Stock Option Plan expire
        unexercised and the corresponding shares are awarded under the 1999
        Stock Incentive Plan.



<PAGE>   3

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT



Item 3. Incorporation of Documents by Reference

        Quintus Corporation (the "Registrant") hereby incorporates by reference
into this Registration Statement the following documents previously filed with
the Securities and Exchange Commission (the "SEC"):

        (a)     The Registrant's prospectus filed with the SEC pursuant to Rule
                424(b) under the Securities Act of 1933, as amended (the "1933
                Act"), in connection with Registration Statement No. 333-86919
                on Form S-1 filed with the SEC on September 10, 1999, together
                with any and all amendments thereto, in which there are set
                forth audited financial statements for the Registrant's fiscal
                years ended March 31, 1997, 1998, and 1999, and

        (b)     The description of the Registrant's outstanding Common Stock
                contained in the Registrant's Registration Statement No.
                000-27985 on Form 8-A12G filed with the SEC on November 11,
                1999, pursuant to Section 12 of the 1934 Act, including any
                amendment or report filed for the purpose of updating such
                description.

        All reports and definitive proxy or information statements filed
pursuant to Section 13(a), 13(c), 14 or 15(d) of the 1934 Act 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 into this Registration Statement and to be a part
hereof from the date of filing of such documents.

Item 4. Description of Securities

        Not Applicable.

Item 5. Interests of Named Experts and Counsel

        Not Applicable.

Item 6. Indemnification of Directors and Officers

        Section 145 of the Delaware General Corporation Law authorizes a court
to award or a corporation's Board of Directors to grant indemnification to
directors and officers in terms sufficiently broad to permit such
indemnification under certain circumstances for liabilities (including
reimbursement for expenses incurred) arising under the 1933 Act. The
Registrant's Bylaws provide for mandatory indemnification of its directors and
permissible indemnification of officers, employees and other agents to the
maximum extent permitted by the Delaware General Corporation Law. The
Registrant's Certificate of Incorporation provides that, pursuant to Delaware
law, its directors shall not be liable for monetary damages for breach of their
fiduciary duty as directors to the Registrant and its stockholders. This
provision in the Certificate of Incorporation does not eliminate the fiduciary
duty of the directors, and, in appropriate circumstances, equitable remedies
such as injunctive or other forms of non-monetary relief will remain available
under Delaware law. In addition, each director will continue to be subject to
liability for breach of the director's duty of loyalty to the Registrant for
acts or omissions not in good faith or involving intentional misconduct, for
knowing violations of law, for actions leading to improper personal benefit to
the director and for payment of dividends or approval of stock repurchases or
redemptions that are unlawful under Delaware law. The provision also does not
affect a director's responsibilities under any other law, such as the federal
securities laws or state or federal environmental laws. The Registrant has
entered into Indemnification Agreements with its directors. The Indemnification
Agreements provide the Registrant's directors with further indemnification to
the maximum extent permitted by the Delaware General Corporation Law.



                                      II-2
<PAGE>   4

Item 7. Exemption from Registration Claimed

        Not Applicable.

Item 8. Exhibits

<TABLE>
<CAPTION>
Exhibit Number  Exhibit
--------------  -------
<S>             <C>
        4       Instrument Defining Rights of Stockholders. Reference is made to
                Registrant's Registration Statement No. 000-27985 on Form
                8-A12G, which is incorporated herein by reference pursuant to
                Item 3(b) of this Registration Statement.

        5       Opinion and consent of Gunderson Dettmer Stough Villeneuve
                Franklin & Hachigian, LLP.

        23.1    Consent of Deloitte & Touche, Independent Auditors.

        23.2    Consent of Gunderson Dettmer Stough Villeneuve Franklin &
                Hachigian, LLP is contained in Exhibit 5.

        23.3    Consent of Ernst & Young LLP, Independent Auditors

        23.4    Consent of PricewaterhouseCoopers LLP, Independent Accountants

        24      Power of Attorney. Reference is made to page II-4 of this
                Registration Statement.
</TABLE>

Item 9. Undertakings

                A. The undersigned Registrant hereby undertakes: (1) to file,
during any period in which offers or sales are being made, a post-effective
amendment to this Registration Statement (i) to include any prospectus required
by Section 10(a)(3) of the 1933 Act, (ii) to reflect in the prospectus any facts
or events arising after the effective date of this 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 this
Registration Statement and (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 this
Registration Statement; provided, however, that clauses (1)(i) and (1)(ii) shall
not apply if the information required to be included in a post-effective
amendment by those paragraphs is contained in periodic reports filed with or
furnished to the SEC by the Registrant pursuant to Section 13 or Section 15(d)
of the 1934 Act that are incorporated by reference in this Registration
Statement; (2) that for the purpose of determining any liability under the 1933
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 and (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 Registrant's 1995 Stock Option Plan, 1999 Stock Plan, 1999
Director Option Plan, Employee Stock Purchase Plan, and 1999 Stock Incentive
Plan.

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

                C. Insofar as indemnification for liabilities arising under the
1933 Act may be permitted to directors, officers or controlling persons of the
Registrant pursuant to the indemnification provisions summarized in Item 6 or
otherwise, the Registrant has been advised that, in the opinion of the SEC, such
indemnification is against public policy as expressed in the 1933 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 1933 Act and will be governed by the final
adjudication of such issue.



                                      II-3
<PAGE>   5

                                   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 Fremont, State of California on this 22nd day of
November, 1999.


                                         QUINTUS CORPORATION


                                         By: /s/ ALAN ANDERSON
                                            ------------------------------------
                                            Alan Anderson
                                            Chairman and Chief Executive Officer




                                POWER OF ATTORNEY



KNOW ALL PERSONS BY THESE PRESENTS:

                That the undersigned officers and directors of Quintus
Corporation, a Delaware corporation, do hereby constitute and appoint Alan
Anderson and Susan Salvesen, and either of them, the lawful attorneys-in-fact
and agents with full power and authority to do any and all acts and things and
to execute any and all instruments which said attorneys and agents, and either
one of them, determine may be necessary or advisable or required to enable said
corporation to comply with the Securities Act of 1933, as amended, and any rules
or regulations or requirements of the Securities and Exchange Commission in
connection with this Registration Statement. Without limiting the generality of
the foregoing power and authority, the powers granted include the power and
authority to sign the names of the undersigned officers and directors in the
capacities indicated below to this Registration Statement, to any and all
amendments, both pre-effective and post-effective, and supplements to this
Registration Statement, and to any and all instruments or documents filed as
part of or in conjunction with this Registration Statement or amendments or
supplements thereof, and each of the undersigned hereby ratifies and confirms
all that said attorneys and agents, or either one of them, shall do or cause to
be done by virtue hereof. This Power of Attorney may be signed in several
counterparts.

                IN WITNESS WHEREOF, each of the undersigned has executed this
Power of Attorney as of the date indicated.

                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 dates indicated.

<TABLE>
<CAPTION>
Signature                               Title                                             Date
---------                               -----                                             ----
<S>                                     <C>                                               <C>
/s/ ALAN ANDERSON                       Chairman and Chief Executive Officer              November 22, 1999
----------------------------------      (Principal Executive Officer)
Alan Anderson

/s/ SUSAN SALVESEN                      Chief Financial Officer
----------------------------------      (Principal Financial and Accounting Officer)      November 22, 1999
Susan Salvesen
</TABLE>



                                      II-4
<PAGE>   6

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

/s/ PAUL BARTLETT                       Director                     November 19, 1999
----------------------------------
Paul Bartlett

                                        Director
----------------------------------
Andrew Busey

/s/ FREDRIC HARMAN                      Director                     November 19, 1999
----------------------------------
Fredric Harman

/s/ WILLIAM HERMAN                      Director                     November 19, 1999
----------------------------------
William Herman

/s/ ALEXANDER ROSEN                     Director                     November 19, 1999
----------------------------------
Alexander Rosen

                                        Director
----------------------------------
Robert Shaw

/s/ JEANNE WOHLERS                      Director                     November 19, 1999
----------------------------------
Jeanne Wohlers
</TABLE>



                                      II-5
<PAGE>   7

                                  EXHIBIT INDEX




<TABLE>
<CAPTION>
Exhibit Number  Exhibit
--------------  -------
<S>             <C>
        4       Instrument Defining Rights of Stockholders. Reference is made to
                Registrant's Registration Statement No. 000-27985 on Form 8-A,
                which is incorporated herein by reference pursuant to Item 3(b)
                of this Registration Statement.
        5       Opinion and consent of Gunderson Dettmer Stough Villeneuve
                Franklin & Hachigian.
        23.1    Consent of Deloitte & Touche LLP, Independent Auditors.
        23.2    Consent of Gunderson Dettmer Stough Villeneuve Franklin &
                Hachigian is contained in Exhibit 5.
        23.3    Consent of Ernst & Young LLP, Independent Auditors
        23.4    Consent of PricewaterhouseCoopers LLP, Independent Accountants
        24      Power of Attorney. Reference is made to page II-4 of this
                Registration Statement.
</TABLE>
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 19985}]
{"company-data": {"conformed-name": "QUINTUS CORP", "cik": "0001024678", "assigned-sic": "7372", "irs-number": "770021612", "state-of-incorporation": "DE", "fiscal-year-end": "0331"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-91453", "film-number": "99762355"}, "business-address": {"street1": "47212 MISSION FALLS COURT", "city": "FREMONT", "state": "CA", "zip": "94539", "phone": "5106242800"}, "mail-address": {"street1": "47212 MISSION FALLS COURT", "city": "FREMONT", "state": "CA", "zip": "94539"}}
1

       As filed with the Securities and Exchange Commission on November 22, 1999
                                                       Registration No. 333-____
================================================================================

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

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

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

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

                               QUINTUS CORPORATION
             (Exact name of registrant as specified in its charter)
DELAWARE                             7372                      77-0021612
     (State or other jurisdiction       (Primary Standard Industrial         (IRS Employer
   of incorporation or organization)     Classification Code Number)      Identification No.)
47212 MISSION FALL COURT
                            FREMONT, CALIFORNIA 94539
               (Address of principal executive offices) (Zip Code)

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

                               QUINTUS CORPORATION
                             1995 STOCK OPTION PLAN
                                 1999 STOCK PLAN
                            1999 DIRECTOR OPTION PLAN
                           EMPLOYEE STOCK PURCHASE PLAN
                            1999 STOCK INCENTIVE PLAN
                            (Full title of the Plans)

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

                                 SUSAN SALVESEN
                             CHIEF FINANCIAL OFFICER
                               QUINTUS CORPORATION
                            47212 MISSION FALLS COURT
                            FREMONT, CALIFORNIA 94539
                     (Name and address of agent for service)
                                 (510) 624-2800
          (Telephone number, including area code, of agent for service)

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

                         CALCULATION OF REGISTRATION FEE
========================================================================================================================
         Title of                                                    Proposed Maximum  Proposed Maximum
        Securities                                 Amount                Offering          Aggregate          Amount of
           to be                                   to be                   Price           Offering         Registration
        Registered                             Registered (1)          per Share (2)       Price (2)             Fee
        ----------                             --------------          -------------       ---------             ---
1995 Stock Option Plan(3)
    Options                                     2,215,242                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           2,215,242 shares         $    18.00         $39,874,356         $11,085.07

1999 Stock Incentive Plan(3)
    Options                                     1,000,000                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           1,000,000 shares         $    18.00         $18,000,000         $ 5,004.00

1999 Stock Plan
    Options                                       422,867                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           422,867 shares           $    18.00         $ 7,611,606         $ 2,116.03
2
1999 Director Option Plan
    Options                                       500,000                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           500,000 shares           $    18.00         $ 9,000,000         $ 2,502.00

Employee Stock Purchase Plan
    Right to Purchase                           1,000,000                     N/A                 N/A                N/A
    Common Stock (par value $.0001)           1,000,000 shares         $    18.00         $18,000,000         $ 5,004.00
(1)     This Registration Statement shall also cover any additional shares of
        Common Stock which become issuable under the 1995 Stock Option Plan,
        1999 Stock Plan, 1999 Director Option Plan, Employee Stock Purchase
        Plan, and 1999 Stock Incentive Plan by reason of any stock dividend,
        stock split, recapitalization or other similar transaction effected
        without the receipt of consideration which results in an increase in the
        number of the outstanding shares of Common Stock of Quintus Corporation.

(2)     Calculated solely for purposes of this offering under Rule 457(h) of the
        Securities Act of 1933, as amended, on the basis of the fair market
        value per share of Common Stock of Quintus Corporation on November 15,
        1999.

(3)     The 2,215,242 shares reserved under the 1995 Stock Option Plan will
        become issuable under the 1999 Stock Incentive Plan if and to the extent
        that options outstanding under the 1995 Stock Option Plan expire
        unexercised and the corresponding shares are awarded under the 1999
        Stock Incentive Plan.
3

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

        Quintus Corporation (the "Registrant") hereby incorporates by reference
into this Registration Statement the following documents previously filed with
the Securities and Exchange Commission (the "SEC"):

        (a)     The Registrant's prospectus filed with the SEC pursuant to Rule
                424(b) under the Securities Act of 1933, as amended (the "1933
                Act"), in connection with Registration Statement No. 333-86919
                on Form S-1 filed with the SEC on September 10, 1999, together
                with any and all amendments thereto, in which there are set
                forth audited financial statements for the Registrant's fiscal
                years ended March 31, 1997, 1998, and 1999, and

        (b)     The description of the Registrant's outstanding Common Stock
                contained in the Registrant's Registration Statement No.
                000-27985 on Form 8-A12G filed with the SEC on November 11,
                1999, pursuant to Section 12 of the 1934 Act, including any
                amendment or report filed for the purpose of updating such
                description.

        All reports and definitive proxy or information statements filed
pursuant to Section 13(a), 13(c), 14 or 15(d) of the 1934 Act 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 into this Registration Statement and to be a part
hereof from the date of filing of such documents.

Item 4. Description of Securities

        Not Applicable.

Item 5. Interests of Named Experts and Counsel

        Not Applicable.

Item 6. Indemnification of Directors and Officers

        Section 145 of the Delaware General Corporation Law authorizes a court
to award or a corporation's Board of Directors to grant indemnification to
directors and officers in terms sufficiently broad to permit such
indemnification under certain circumstances for liabilities (including
reimbursement for expenses incurred) arising under the 1933 Act. The
Registrant's Bylaws provide for mandatory indemnification of its directors and
permissible indemnification of officers, employees and other agents to the
maximum extent permitted by the Delaware General Corporation Law. The
Registrant's Certificate of Incorporation provides that, pursuant to Delaware
law, its directors shall not be liable for monetary damages for breach of their
fiduciary duty as directors to the Registrant and its stockholders. This
provision in the Certificate of Incorporation does not eliminate the fiduciary
duty of the directors, and, in appropriate circumstances, equitable remedies
such as injunctive or other forms of non-monetary relief will remain available
under Delaware law. In addition, each director will continue to be subject to
liability for breach of the director's duty of loyalty to the Registrant for
acts or omissions not in good faith or involving intentional misconduct, for
knowing violations of law, for actions leading to improper personal benefit to
the director and for payment of dividends or approval of stock repurchases or
redemptions that are unlawful under Delaware law. The provision also does not
affect a director's responsibilities under any other law, such as the federal
securities laws or state or federal environmental laws. The Registrant has
entered into Indemnification Agreements with its directors. The Indemnification
Agreements provide the Registrant's directors with further indemnification to
the maximum extent permitted by the Delaware General Corporation Law.

                                      II-2
4

Item 7. Exemption from Registration Claimed

        Not Applicable.

Item 8. Exhibits
Exhibit Number  Exhibit
--------------  -------
4       Instrument Defining Rights of Stockholders. Reference is made to
                Registrant's Registration Statement No. 000-27985 on Form
                8-A12G, which is incorporated herein by reference pursuant to
                Item 3(b) of this Registration Statement.

        5       Opinion and consent of Gunderson Dettmer Stough Villeneuve
                Franklin & Hachigian, LLP.

        23.1    Consent of Deloitte & Touche, Independent Auditors.

        23.2    Consent of Gunderson Dettmer Stough Villeneuve Franklin &
                Hachigian, LLP is contained in Exhibit 5.

        23.3    Consent of Ernst & Young LLP, Independent Auditors

        23.4    Consent of PricewaterhouseCoopers LLP, Independent Accountants

        24      Power of Attorney. Reference is made to page II-4 of this
                Registration Statement.
Item 9. Undertakings

                A. The undersigned Registrant hereby undertakes: (1) to file,
during any period in which offers or sales are being made, a post-effective
amendment to this Registration Statement (i) to include any prospectus required
by Section 10(a)(3) of the 1933 Act, (ii) to reflect in the prospectus any facts
or events arising after the effective date of this 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 this
Registration Statement and (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 this
Registration Statement; provided, however, that clauses (1)(i) and (1)(ii) shall
not apply if the information required to be included in a post-effective
amendment by those paragraphs is contained in periodic reports filed with or
furnished to the SEC by the Registrant pursuant to Section 13 or Section 15(d)
of the 1934 Act that are incorporated by reference in this Registration
Statement; (2) that for the purpose of determining any liability under the 1933
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 and (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 Registrant's 1995 Stock Option Plan, 1999 Stock Plan, 1999
Director Option Plan, Employee Stock Purchase Plan, and 1999 Stock Incentive
Plan.

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

                C. Insofar as indemnification for liabilities arising under the
1933 Act may be permitted to directors, officers or controlling persons of the
Registrant pursuant to the indemnification provisions summarized in Item 6 or
otherwise, the Registrant has been advised that, in the opinion of the SEC, such
indemnification is against public policy as expressed in the 1933 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 1933 Act and will be governed by the final
adjudication of such issue.

                                      II-3
5

                                   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 Fremont, State of California on this 22nd day of
November, 1999.

                                         QUINTUS CORPORATION

                                         By: /s/ ALAN ANDERSON
                                            ------------------------------------
                                            Alan Anderson
                                            Chairman and Chief Executive Officer

                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

                That the undersigned officers and directors of Quintus
Corporation, a Delaware corporation, do hereby constitute and appoint Alan
Anderson and Susan Salvesen, and either of them, the lawful attorneys-in-fact
and agents with full power and authority to do any and all acts and things and
to execute any and all instruments which said attorneys and agents, and either
one of them, determine may be necessary or advisable or required to enable said
corporation to comply with the Securities Act of 1933, as amended, and any rules
or regulations or requirements of the Securities and Exchange Commission in
connection with this Registration Statement. Without limiting the generality of
the foregoing power and authority, the powers granted include the power and
authority to sign the names of the undersigned officers and directors in the
capacities indicated below to this Registration Statement, to any and all
amendments, both pre-effective and post-effective, and supplements to this
Registration Statement, and to any and all instruments or documents filed as
part of or in conjunction with this Registration Statement or amendments or
supplements thereof, and each of the undersigned hereby ratifies and confirms
all that said attorneys and agents, or either one of them, shall do or cause to
be done by virtue hereof. This Power of Attorney may be signed in several
counterparts.

                IN WITNESS WHEREOF, each of the undersigned has executed this
Power of Attorney as of the date indicated.

                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 dates indicated.
Signature                               Title                                             Date
---------                               -----                                             ----
/s/ ALAN ANDERSON                       Chairman and Chief Executive Officer              November 22, 1999
----------------------------------      (Principal Executive Officer)
Alan Anderson

/s/ SUSAN SALVESEN                      Chief Financial Officer
----------------------------------      (Principal Financial and Accounting Officer)      November 22, 1999
Susan Salvesen
II-4
6
Signature                               Title                        Date
---------                               -----                        ----
/s/ PAUL BARTLETT                       Director                     November 19, 1999
----------------------------------
Paul Bartlett

                                        Director
----------------------------------
Andrew Busey

/s/ FREDRIC HARMAN                      Director                     November 19, 1999
----------------------------------
Fredric Harman

/s/ WILLIAM HERMAN                      Director                     November 19, 1999
----------------------------------
William Herman

/s/ ALEXANDER ROSEN                     Director                     November 19, 1999
----------------------------------
Alexander Rosen

                                        Director
----------------------------------
Robert Shaw

/s/ JEANNE WOHLERS                      Director                     November 19, 1999
----------------------------------
Jeanne Wohlers
II-5
7

                                  EXHIBIT INDEX
Exhibit Number  Exhibit
--------------  -------
4       Instrument Defining Rights of Stockholders. Reference is made to
                Registrant's Registration Statement No. 000-27985 on Form 8-A,
                which is incorporated herein by reference pursuant to Item 3(b)
                of this Registration Statement.
        5       Opinion and consent of Gunderson Dettmer Stough Villeneuve
                Franklin & Hachigian.
        23.1    Consent of Deloitte & Touche LLP, Independent Auditors.
        23.2    Consent of Gunderson Dettmer Stough Villeneuve Franklin &
                Hachigian is contained in Exhibit 5.
        23.3    Consent of Ernst & Young LLP, Independent Auditors
        23.4    Consent of PricewaterhouseCoopers LLP, Independent Accountants
        24      Power of Attorney. Reference is made to page II-4 of this
                Registration Statement.