<PAGE>   1
   As filed with the Securities and Exchange Commission on December 30, 1998
                                                Registration No. 333-___________



                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      Under
                           The Securities Act of 1933

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

                               ACT NETWORKS, INC.
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                            <C>
           DELAWARE                                      77-0396887
 (State or other jurisdiction                  (IRS Employer Identification No.)
of incorporation or organization)
</TABLE>
                                 188 CAMINO RUIZ
                           CAMARILLO, CALIFORNIA 93012
                                 (805) 388-2474
               (Address of principal executive offices) (Zip Code)

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

           1997 NON-EXECUTIVE OFFICER STOCK OPTION/STOCK ISSUANCE PLAN
                          EMPLOYEE STOCK PURCHASE PLAN
                           (Full titles of the Plans)

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

                                 SUSAN N. CAYLEY
                               V.P., LEGAL AFFAIRS
                               ACT NETWORKS, INC.
                                 188 CAMINO RUIZ
                           CAMARILLO, CALIFORNIA 93012
                                 (805) 388-2474

                     (Name and address of agent for service)

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

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
                                                                  Proposed             Proposed
            Title of                                               Maximum              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>
1997 Non-Executive Officer Stock
Option/Stock Issuance Plan

Common Stock, $0.001 par value            200,000 shares          $12.72               $2,544,000              $  707.23

Employee Stock Purchase Plan                                                                             

Common Stock, $0.001 par value            150,000 shares          $12.72               $1,908,000              $  530.42
                                                                                                               ---------
                                                                                       Aggregate Filing Fee    $1,237.65
</TABLE>

(1)  This Registration Statement shall also cover any additional shares of
     Common Stock which become issuable under the 1997 Non-Executive Officer
     Stock Option/Stock Issuance Plan and the Employee Stock Purchase Plan by
     reason of any stock dividend, stock split, recapitalization or other
     similar transaction effected without the Registrant's receipt of
     consideration which results in an increase in the number of the outstanding
     shares of Registrant's Common Stock.

(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 average of the high
     and low selling prices per share of Registrant's Common Stock on December
     24, 1998, as reported by the Nasdaq National Market.

<PAGE>   2



                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

     ACT Networks, Inc. (the "Registrant") hereby incorporates by reference into
this Registration Statement the following documents previously filed with the
Securities and Exchange Commission (the "Commission"):


     (a)  The Registrant's Annual Report on Form 10-K/A for the fiscal year
          ended June 30, 1998, filed with the Commission on October 14, 1998;

     (b)  The Registrant's Quarterly Report on Form 10-Q for the fiscal quarter
          ended September 30, 1998, filed with the Commission on November 16,
          1998;

     (c)  The Registrant's Registration Statement No. 000-25740 on Form 8-A, as
          amended, filed with the Commission on March 23, 1995 in which the
          terms, rights and provisions applicable to the Registrant's Common
          Stock are described, and

     (d)  The Registrant's Registration Statement No. 000-25740 on Form 8-A/a,
          as amended, filed with the Commission on April 25, 1995 in which the
          terms, rights and provisions applicable to the Registrant's Common
          Stock are described.

     All reports and definitive proxy or information statements filed pursuant
to Section 13(a), 13(c), 14 or 15(d) of the Securities and Exchange Act of 1934,
as amended (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. Any statement contained in a document incorporated or deemed to be
incorporated by reference herein shall be deemed to be modified or superseded
for purposes of this Registration Statement to the extent that a statement
contained herein or in any subsequently filed document which also is deemed to
be incorporated by reference herein modifies or supersedes such statement. Any
such statement so modified or superseded shall not be deemed, except as so
modified or superseded, to constitute a part of this Registration Statement.


Item 4. Description of Securities

     Not Applicable.


Item 5. Interests of Named Experts and Counsel

     Not Applicable.

<PAGE>   3

Item 6. Indemnification of Directors and Officers

     Under Section 145 of the Delaware General Corporation Law, the Registrant
has broad powers to indemnify its directors and officers against liabilities
they may incur in such capacities, including liabilities under the Securities
Act of 1933, as amended (the "1933 Act"). The Registrant's Bylaws (the "Bylaws")
provide that the Registrant shall indemnify its directors and officers to the
extent any such officer or director acted (i) in good faith, (ii) in a manner
reasonably believed to be in or not opposed to the best interests of the
Registrant, and (iii) with respect to any criminal action or proceeding, with
reasonable cause to believe such conduct was lawful. The Registrant believes
that indemnification under its Bylaws covers at least negligence and gross
negligence and requires the Registrant to advance litigation expenses in the
case of stockholder derivative actions or other actions, against an undertaking
by the director or officer to repay such advances if it is ultimately determined
that such individual is not entitled to indemnification. The Bylaws further
provide that rights conferred under such Bylaws shall not be deemed to be
exclusive of any other right such person may have or acquire under any
agreement, vote of stockholders or disinterested directors, or otherwise.

     In addition, the Registrant's Certificate of Incorporation (the
"Certificate of Incorporation") provides that, pursuant to Delaware law, no
director shall be liable for monetary damages for breach of his or her fiduciary
duty of care to the Registrant and its stockholders. This provision in the
Certificate of Incorporation does not eliminate the duty of care, 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 Certificate of Incorporation further
provides that the Registrant shall indemnify its directors and officers to the
fullest extent permitted by law and requires the Registrant to advance
litigation expenses in the case of stockholder derivative actions or other
actions, against an undertaking by the director to repay such advances if it is
ultimately determined that the director is not entitled to indemnification. The
Certificate of Incorporation also provides that rights conferred under such
Certificate of Incorporation shall not be deemed to be exclusive of any other
right such person may have or acquire under any statute, the Certificate of
Incorporation, the Bylaws or any agreement, vote of stockholders or
disinterested directors, or otherwise.

     The Registrant has obtained a liability insurance policy for its officers
and directors that, subject to certain limitations, terms and conditions, will
insure them against losses arising from wrongful acts (as defined by the policy)
in their capacity as directors or officers.

     In addition, the Registrant has entered into agreements to indemnify its
directors and certain of its officers in addition to the indemnification
provided for in the Certificate of Incorporation and Bylaws. These agreements,
among other things, indemnify the Registrant's directors and certain of its
officers for certain expenses (including attorneys fees), judgments, fines and
settlement amounts incurred by such person in any action or proceeding,
including any action by or in the right of the Registrant, on account of
services as a director or officer of the Registrant or as a director or officer
of any subsidiary of the Registrant, or as a director or officer of any other
company or enterprise that the person provides services to at the request of the
Registrant.

Item 7. Exemption from Registration Claimed

         Not Applicable.

<PAGE>   4

Item 8. Exhibits

<TABLE>
<CAPTION>
Number       Exhibit
------       -------
<S>          <C>
4            Instruments Defining the Rights of Stockholders. Reference is made to 
             the Registrant's Registration Statement No. 000-25740 on Form 8-A, and
             the amendment thereto on Form 8-A/a, which are incorporated herein by
             reference pursuant to Items 3(c) and 3(d), respectively, of this
             Registration Statement.

5            Opinion and consent of Brobeck, Phleger & Harrison LLP.

23.1         Consent of Ernst & Young LLP, Independent Accountants.

23.2         Consent of Brobeck, Phleger & Harrison LLP is contained in Exhibit 5.

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

99.1         1997 Non-Executive Officer Stock Option/Stock Issuance Plan (as amended 
             July 10, 1998).

99.2*        Form of Notice of Grant of Stock Option to be generally used in connection 
             with the 1997 Non-Executive Officer Stock Option/Stock Issuance Plan.

99.3*        Form of Stock Option Agreement to be generally used in connection with the 
             Discretionary Option Grant Program of the 1997 Non-Executive Officer Stock
             Option/Stock Issuance Plan.

99.4*        Form of Addendum to Stock Option Agreement (Involuntary Termination 
             Following Change in Control).

99.5         Employee Stock Purchase Plan.

99.6**       Form of Enrollment/Change Form to be generally used in connection with the 
             Employee Stock Purchase Plan.

99.7**       Form of Stock Purchase Agreement to be generally used in connection with 
             the Employee Stock Purchase Plan.
</TABLE>

*  Exhibits 99.2 through 99.4 are incorporated herein by reference to Exhibits
   10.29 through 10.31, respectively, to Registrant's quarterly report for the
   quarter ended March 31, 1997, filed with the Commission on May 15, 1997.

** Exhibits 99.6 through 99.7 are incorporated herein by reference to Exhibits
   99.14 through 99.15, respectively, to Registrant's Registration Statement on
   Form S-8, Registration No. 33-80007.


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 by the
Registrant pursuant to Section 13 or Section 15(d) of the 1934 Act that are
incorporated by reference into 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 1997
Non-Executive Officer Stock Option/Stock Issuance Plan or the Registrant's
Employee Stock Purchase 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 into 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.

<PAGE>   5

     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 Commission, 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.


                                   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 Camarillo, State of California on this 28th day
of December, 1998.


                                       ACT NETWORKS, INC.


                                       By: /s/ Andre de Fusco
                                           -------------------------------------
                                           Andre de Fusco
                                           Chief Executive Officer and Director


                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

     That the undersigned officers and directors of ACT Networks, Inc., a
Delaware corporation, do hereby constitute and appoint Andre de Fusco and Greg
Gutierrez and each 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 any 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 that all said
attorneys and agents, or any 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.

<PAGE>   6

<TABLE>
<CAPTION>
Signature                                Title                                  Date
---------                                -----                                  ----
<S>                                      <C>                                    <C>
                                   
/s/ Andre de Fusco                       Chief Executive Officer
-------------------------------          and Director                           December 28, 1998
Andre de Fusco                           (Principal Executive Officer)                


/s/ Greg Gutierrez                       Controller                             December 28, 1998
-------------------------------          (Principal Financial and               
Greg Gutierrez                           Accounting Officer)


                                         Director
-------------------------------                                                 
William Ambrose


                                         Director
-------------------------------
Harold R. Johnson              


/s/ Archie J. McGill                     Director                               December 28, 1998
-------------------------------        
Archie J. McGill                       


/s/ Frederick N. Gluck                   Director                               December 21, 1998
-------------------------------
Frederick N. Gluck
</TABLE>

<PAGE>   7



                       SECURITIES AND EXCHANGE COMMISSION

                                WASHINGTON, D.C.



                                    EXHIBITS

                                       TO

                                    FORM S-8

                                      UNDER

                             SECURITIES ACT OF 1933


                               ACT NETWORKS, INC.



<PAGE>   8

                                  EXHIBIT INDEX

<TABLE>
<CAPTION>
Number       Exhibit
------       -------
<S>          <C>
4            Instruments Defining the Rights of Stockholders. Reference is made to 
             the Registrant's Registration Statement No. 000-25740 on Form 8-A, and 
             the amendment thereto on Form 8-A/a, which are incorporated  herein by 
             reference pursuant to Items 3(c) and 3(d), respectively, of this 
             Registration Statement.

5            Opinion and consent of Brobeck, Phleger & Harrison LLP.

23.1         Consent of Ernst & Young LLP, Independent Accountants.

23.2         Consent of Brobeck, Phleger & Harrison LLP is contained in Exhibit 5.

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

99.1         1997 Non-Executive Officer Stock Option/Stock Issuance Plan (as amended 
             July 10, 1998).

99.2*        Form of Notice of Grant of Stock Option to be generally used in connection 
             with the 1997 Non-Executive Officer Stock Option/Stock Issuance Plan.

99.3*        Form of Stock Option Agreement to be generally used in connection with the 
             Discretionary Option Grant Program of the 1997 Non-Executive Officer Stock
             Option/Stock Issuance Plan.

99.4*        Form of Addendum to Stock Option Agreement (Involuntary Termination 
             Following Change in Control).

99.5         Employee Stock Purchase Plan.

99.6**       Form of Enrollment/Change Form to be generally used in connection with the 
             Employee Stock Purchase Plan.

99.7**       Form of Stock Purchase Agreement to be generally used in connection with 
             the Employee Stock Purchase Plan.
</TABLE>

*  Exhibits 99.2 through 99.4 are incorporated herein by reference to Exhibits
   10.29 through 10.31, respectively, to Registrant's quarterly report for the
   quarter ended March 31, 1997, filed with the Commission on May 15, 1997.

** Exhibits 99.6 through 99.7 are incorporated herein by reference to Exhibits
   99.14 through 99.15, respectively, to Registrant's Registration Statement on
   Form S-8, Registration No. 33-80007.
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 23259}]
{"company-data": {"conformed-name": "ACT NETWORKS INC", "cik": "0000942132", "assigned-sic": "3576", "irs-number": "770396887", "state-of-incorporation": "DE", "fiscal-year-end": "0630"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-69935", "film-number": "98778496"}, "business-address": {"street1": "188 CAMINO RD", "city": "CAMARILLO", "state": "CA", "zip": "93012", "phone": "8053882474"}, "mail-address": {"street1": "188 CAMINO RUIZ", "city": "CAMARILLO", "state": "CA", "zip": "93012"}}
1
   As filed with the Securities and Exchange Commission on December 30, 1998
                                                Registration No. 333-___________

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      Under
                           The Securities Act of 1933

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

                               ACT NETWORKS, INC.
             (Exact name of registrant as specified in its charter)
DELAWARE                                      77-0396887
 (State or other jurisdiction                  (IRS Employer Identification No.)
of incorporation or organization)
188 CAMINO RUIZ
                           CAMARILLO, CALIFORNIA 93012
                                 (805) 388-2474
               (Address of principal executive offices) (Zip Code)

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

           1997 NON-EXECUTIVE OFFICER STOCK OPTION/STOCK ISSUANCE PLAN
                          EMPLOYEE STOCK PURCHASE PLAN
                           (Full titles of the Plans)

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

                                 SUSAN N. CAYLEY
                               V.P., LEGAL AFFAIRS
                               ACT NETWORKS, INC.
                                 188 CAMINO RUIZ
                           CAMARILLO, CALIFORNIA 93012
                                 (805) 388-2474

                     (Name and address of agent for service)

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

                         CALCULATION OF REGISTRATION FEE
Proposed             Proposed
            Title of                                               Maximum              Maximum
           Securities                        Amount               Offering             Aggregate             Amount of
              to be                          to be                  Price              Offering             Registration
           Registered                     Registered(1)          per Share(2)          Price(2)                 Fee
           ----------                     -------------          ------------          ---------            ------------
1997 Non-Executive Officer Stock
Option/Stock Issuance Plan

Common Stock, $0.001 par value            200,000 shares          $12.72               $2,544,000              $  707.23

Employee Stock Purchase Plan                                                                             

Common Stock, $0.001 par value            150,000 shares          $12.72               $1,908,000              $  530.42
                                                                                                               ---------
                                                                                       Aggregate Filing Fee    $1,237.65
(1)  This Registration Statement shall also cover any additional shares of
     Common Stock which become issuable under the 1997 Non-Executive Officer
     Stock Option/Stock Issuance Plan and the Employee Stock Purchase Plan by
     reason of any stock dividend, stock split, recapitalization or other
     similar transaction effected without the Registrant's receipt of
     consideration which results in an increase in the number of the outstanding
     shares of Registrant's Common Stock.

(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 average of the high
     and low selling prices per share of Registrant's Common Stock on December
     24, 1998, as reported by the Nasdaq National Market.
2

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

     ACT Networks, Inc. (the "Registrant") hereby incorporates by reference into
this Registration Statement the following documents previously filed with the
Securities and Exchange Commission (the "Commission"):

     (a)  The Registrant's Annual Report on Form 10-K/A for the fiscal year
          ended June 30, 1998, filed with the Commission on October 14, 1998;

     (b)  The Registrant's Quarterly Report on Form 10-Q for the fiscal quarter
          ended September 30, 1998, filed with the Commission on November 16,
          1998;

     (c)  The Registrant's Registration Statement No. 000-25740 on Form 8-A, as
          amended, filed with the Commission on March 23, 1995 in which the
          terms, rights and provisions applicable to the Registrant's Common
          Stock are described, and

     (d)  The Registrant's Registration Statement No. 000-25740 on Form 8-A/a,
          as amended, filed with the Commission on April 25, 1995 in which the
          terms, rights and provisions applicable to the Registrant's Common
          Stock are described.

     All reports and definitive proxy or information statements filed pursuant
to Section 13(a), 13(c), 14 or 15(d) of the Securities and Exchange Act of 1934,
as amended (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. Any statement contained in a document incorporated or deemed to be
incorporated by reference herein shall be deemed to be modified or superseded
for purposes of this Registration Statement to the extent that a statement
contained herein or in any subsequently filed document which also is deemed to
be incorporated by reference herein modifies or supersedes such statement. Any
such statement so modified or superseded shall not be deemed, except as so
modified or superseded, to constitute a part of this Registration Statement.

Item 4. Description of Securities

     Not Applicable.

Item 5. Interests of Named Experts and Counsel

     Not Applicable.
3

Item 6. Indemnification of Directors and Officers

     Under Section 145 of the Delaware General Corporation Law, the Registrant
has broad powers to indemnify its directors and officers against liabilities
they may incur in such capacities, including liabilities under the Securities
Act of 1933, as amended (the "1933 Act"). The Registrant's Bylaws (the "Bylaws")
provide that the Registrant shall indemnify its directors and officers to the
extent any such officer or director acted (i) in good faith, (ii) in a manner
reasonably believed to be in or not opposed to the best interests of the
Registrant, and (iii) with respect to any criminal action or proceeding, with
reasonable cause to believe such conduct was lawful. The Registrant believes
that indemnification under its Bylaws covers at least negligence and gross
negligence and requires the Registrant to advance litigation expenses in the
case of stockholder derivative actions or other actions, against an undertaking
by the director or officer to repay such advances if it is ultimately determined
that such individual is not entitled to indemnification. The Bylaws further
provide that rights conferred under such Bylaws shall not be deemed to be
exclusive of any other right such person may have or acquire under any
agreement, vote of stockholders or disinterested directors, or otherwise.

     In addition, the Registrant's Certificate of Incorporation (the
"Certificate of Incorporation") provides that, pursuant to Delaware law, no
director shall be liable for monetary damages for breach of his or her fiduciary
duty of care to the Registrant and its stockholders. This provision in the
Certificate of Incorporation does not eliminate the duty of care, 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 Certificate of Incorporation further
provides that the Registrant shall indemnify its directors and officers to the
fullest extent permitted by law and requires the Registrant to advance
litigation expenses in the case of stockholder derivative actions or other
actions, against an undertaking by the director to repay such advances if it is
ultimately determined that the director is not entitled to indemnification. The
Certificate of Incorporation also provides that rights conferred under such
Certificate of Incorporation shall not be deemed to be exclusive of any other
right such person may have or acquire under any statute, the Certificate of
Incorporation, the Bylaws or any agreement, vote of stockholders or
disinterested directors, or otherwise.

     The Registrant has obtained a liability insurance policy for its officers
and directors that, subject to certain limitations, terms and conditions, will
insure them against losses arising from wrongful acts (as defined by the policy)
in their capacity as directors or officers.

     In addition, the Registrant has entered into agreements to indemnify its
directors and certain of its officers in addition to the indemnification
provided for in the Certificate of Incorporation and Bylaws. These agreements,
among other things, indemnify the Registrant's directors and certain of its
officers for certain expenses (including attorneys fees), judgments, fines and
settlement amounts incurred by such person in any action or proceeding,
including any action by or in the right of the Registrant, on account of
services as a director or officer of the Registrant or as a director or officer
of any subsidiary of the Registrant, or as a director or officer of any other
company or enterprise that the person provides services to at the request of the
Registrant.

Item 7. Exemption from Registration Claimed

         Not Applicable.
4

Item 8. Exhibits
Number       Exhibit
------       -------
4            Instruments Defining the Rights of Stockholders. Reference is made to 
             the Registrant's Registration Statement No. 000-25740 on Form 8-A, and
             the amendment thereto on Form 8-A/a, which are incorporated herein by
             reference pursuant to Items 3(c) and 3(d), respectively, of this
             Registration Statement.

5            Opinion and consent of Brobeck, Phleger & Harrison LLP.

23.1         Consent of Ernst & Young LLP, Independent Accountants.

23.2         Consent of Brobeck, Phleger & Harrison LLP is contained in Exhibit 5.

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

99.1         1997 Non-Executive Officer Stock Option/Stock Issuance Plan (as amended 
             July 10, 1998).

99.2*        Form of Notice of Grant of Stock Option to be generally used in connection 
             with the 1997 Non-Executive Officer Stock Option/Stock Issuance Plan.

99.3*        Form of Stock Option Agreement to be generally used in connection with the 
             Discretionary Option Grant Program of the 1997 Non-Executive Officer Stock
             Option/Stock Issuance Plan.

99.4*        Form of Addendum to Stock Option Agreement (Involuntary Termination 
             Following Change in Control).

99.5         Employee Stock Purchase Plan.

99.6**       Form of Enrollment/Change Form to be generally used in connection with the 
             Employee Stock Purchase Plan.

99.7**       Form of Stock Purchase Agreement to be generally used in connection with 
             the Employee Stock Purchase Plan.
*  Exhibits 99.2 through 99.4 are incorporated herein by reference to Exhibits
   10.29 through 10.31, respectively, to Registrant's quarterly report for the
   quarter ended March 31, 1997, filed with the Commission on May 15, 1997.

** Exhibits 99.6 through 99.7 are incorporated herein by reference to Exhibits
   99.14 through 99.15, respectively, to Registrant's Registration Statement on
   Form S-8, Registration No. 33-80007.

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 by the
Registrant pursuant to Section 13 or Section 15(d) of the 1934 Act that are
incorporated by reference into 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 1997
Non-Executive Officer Stock Option/Stock Issuance Plan or the Registrant's
Employee Stock Purchase 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 into 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.
5

     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 Commission, 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.

                                   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 Camarillo, State of California on this 28th day
of December, 1998.

                                       ACT NETWORKS, INC.

                                       By: /s/ Andre de Fusco
                                           -------------------------------------
                                           Andre de Fusco
                                           Chief Executive Officer and Director

                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

     That the undersigned officers and directors of ACT Networks, Inc., a
Delaware corporation, do hereby constitute and appoint Andre de Fusco and Greg
Gutierrez and each 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 any 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 that all said
attorneys and agents, or any 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.
6
Signature                                Title                                  Date
---------                                -----                                  ----
/s/ Andre de Fusco                       Chief Executive Officer
-------------------------------          and Director                           December 28, 1998
Andre de Fusco                           (Principal Executive Officer)                

/s/ Greg Gutierrez                       Controller                             December 28, 1998
-------------------------------          (Principal Financial and               
Greg Gutierrez                           Accounting Officer)

                                         Director
-------------------------------                                                 
William Ambrose

                                         Director
-------------------------------
Harold R. Johnson              

/s/ Archie J. McGill                     Director                               December 28, 1998
-------------------------------        
Archie J. McGill                       

/s/ Frederick N. Gluck                   Director                               December 21, 1998
-------------------------------
Frederick N. Gluck
7

                       SECURITIES AND EXCHANGE COMMISSION

                                WASHINGTON, D.C.

                                    EXHIBITS

                                       TO

                                    FORM S-8

                                      UNDER

                             SECURITIES ACT OF 1933

                               ACT NETWORKS, INC.
8

                                  EXHIBIT INDEX
Number       Exhibit
------       -------
4            Instruments Defining the Rights of Stockholders. Reference is made to 
             the Registrant's Registration Statement No. 000-25740 on Form 8-A, and 
             the amendment thereto on Form 8-A/a, which are incorporated  herein by 
             reference pursuant to Items 3(c) and 3(d), respectively, of this 
             Registration Statement.

5            Opinion and consent of Brobeck, Phleger & Harrison LLP.

23.1         Consent of Ernst & Young LLP, Independent Accountants.

23.2         Consent of Brobeck, Phleger & Harrison LLP is contained in Exhibit 5.

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

99.1         1997 Non-Executive Officer Stock Option/Stock Issuance Plan (as amended 
             July 10, 1998).

99.2*        Form of Notice of Grant of Stock Option to be generally used in connection 
             with the 1997 Non-Executive Officer Stock Option/Stock Issuance Plan.

99.3*        Form of Stock Option Agreement to be generally used in connection with the 
             Discretionary Option Grant Program of the 1997 Non-Executive Officer Stock
             Option/Stock Issuance Plan.

99.4*        Form of Addendum to Stock Option Agreement (Involuntary Termination 
             Following Change in Control).

99.5         Employee Stock Purchase Plan.

99.6**       Form of Enrollment/Change Form to be generally used in connection with the 
             Employee Stock Purchase Plan.

99.7**       Form of Stock Purchase Agreement to be generally used in connection with 
             the Employee Stock Purchase Plan.
*  Exhibits 99.2 through 99.4 are incorporated herein by reference to Exhibits
   10.29 through 10.31, respectively, to Registrant's quarterly report for the
   quarter ended March 31, 1997, filed with the Commission on May 15, 1997.

** Exhibits 99.6 through 99.7 are incorporated herein by reference to Exhibits
   99.14 through 99.15, respectively, to Registrant's Registration Statement on
   Form S-8, Registration No. 33-80007.