<PAGE>   1

       As filed with the Securities and Exchange Commission on November 26, 1996
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                            WASHINGTON, D.C.  20549

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

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


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


         CALIFORNIA                                  33-00444888
(State or other jurisdiction of         (I.R.S. Employer Identification No.)
incorporation or organization)


                              2830 BARRETT AVENUE
                            PERRIS, CALIFORNIA 92370
               (Address of Principal Executive Office)(Zip Code)


                             1996 STOCK OPTION PLAN
                           (Full title of the plans)

                                 EVAN M. GRUBER
                              2830 BARRETT AVENUE
                            PERRIS, CALIFORNIA 92370
                    (Name and address of agent for service)

                                 (909) 943-4014
         (Telephone number, including area code, of agent for service)

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

                        CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
==========================================================================================================
                                                   Proposed         Proposed
Title of                  Amount                   maximum          maximum                   Amount of
securities to             to be                    offering price   aggregate                 registration
be registered             registered               per share (1)    offering price (1)        fee              
----------------------------------------------------------------------------------------------------------
<S>                       <C>                      <C>              <C>                       <C>
Common Stock,             500,000                  $4.50            $2,250,000                $775.86
$.001 par value
==========================================================================================================
</TABLE>


(1)  Pursuant to Rule 457(a), estimated solely for the purpose of calculating
     the registration fee.


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

<PAGE>   2
                                     PART I

                          INFORMATION REQUIRED IN THE
                            SECTION 10(a) PROSPECTUS

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





                                       2
<PAGE>   3
                                    PART II

                          INFORMATION REQUIRED IN THE
                             REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.

         The following documents previously filed by Modtech, Inc. (the
"Company") with the Commission are incorporated herein by reference:

         1.      The Company's Annual Report on Form 10-K for the fiscal year
                 ended December 31, 1995;

         2.      The Company's Quarterly Reports on Form 10-Q for the quarters
                 ended March 31 and June 30, 1996;

         3       The description of the Company's Common Stock contained in the
                 Company's Registration Statement on Form 8-A filed
                 under the Securities Exchange Act of 1934.

All documents subsequently filed by the Company pursuant to Sections 13(a),
13(c), 14 or 15(d) of the Securities and Exchange Act of 1934 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 the
prospectus 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.

         The Company's Articles of Incorporation and Bylaws permit the Company
to indemnify its officers and directors to the fullest extent permitted by
California law.  This is intended to eliminate the personal liability of a
director for monetary damages in an action brought by or in the right of the
Company for breach of a director's duties to the Company or its shareholders
except for liability for acts or omissions that involve intentional misconduct
or knowing and culpable violation of the law, for acts or omissions that a
director believes to be contrary to the best interests of the Company or its
shareholders or that involve the absence of good faith on the part of the
director, for any transaction from which a director derived an improper
personal benefit, for acts or omissions that show a reckless disregard for the
director's duty to the Company or its shareholders in circumstances in which
the director was aware, or should have been aware, in the ordinary course of
performing a director's duties, of a risk of serious injury to the Company or
its shareholders, for acts or omissions that constitute an unexcused pattern of
inattention that amounts to an abdication of the director's duty to the Company
or its shareholders, with respect to certain contracts in which a director has
a material financial interest and for approval of certain improper
distributions to shareholders or certain loans or guarantees.  This provision
does not limit or eliminate the rights of the Company or any shareholder to
seek non-monetary relief such as an injunction or rescission in the event of a
breach of a director's duty of care.

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





                                      II-1


<PAGE>   4
ITEM 7. EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

ITEM 8.  EXHIBITS.

          5.1    Opinion of Phillips & Haddan
         10.1    Modtech, Inc. 1996 Stock Option Plan
         23.1    Consent of KPMG Peat Marwick L.L.P.
         24.2    Consent of Phillips & Haddan (included in Exhibit 5.1).





                                      II-2


<PAGE>   5
ITEM 9.  UNDERTAKINGS.

         The undersigned registrant hereby undertakes:

         (a)(1)  To file, during any period in which offers or sales are being
made, a post-effective amendment to this registration statement:

                 (i)  To include any prospectus required by Section 10(a)(3)
of the Securities Act of 1933 (the "Securities Act");

                (ii)  To reflect in the prospectus any facts or events arising
after the effective date of the registration statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate,
represents a fundamental change in the information set forth in the
registration statement;

               (iii)  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.

                 Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do
not apply if the registration statement is on Form S-3 or Form S-8 and 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 Exchange Act that are incorporated by
reference in the registration statement.

             (2)  That, for the purpose 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.

         (b)  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 (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to 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.

         (h)  Insofar as 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 Securities and Exchange
Commission such indemnification is against pubic policy as expressed in the Act
and is, therefore, unenforceable.  In the event that a  claim for
indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or controlling
person of the registrant in the successful defense of any action, suit or
proceeding) is asserted by such director, officer or controlling person in
connection with the securities being registered, the registrant will, unless in
the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act and will be governed by the final adjudication of such issue.





                                      II-3


<PAGE>   6
         Pursuant to the requirements of the Securities Act of 1933, the
registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Newport Beach, State of California, on November
26, 1996.

                                         MODTECH, INC.

                                By:      s/Evan M. Gruber
                                         ---------------------------------------
                                         Evan M. Gruber, Chief Executive Officer

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons in the
capacities and on the date indicated

<TABLE>
<CAPTION>
Signatures                                             Title                               Date
----------                                             -----                               ----
<S>                                        <C>                                       <C>
s/Evan M. Gruber                           Director, Chief Executive                 November 26, 1996
--------------------------                 Officer
Evan M. Gruber                            


s/Gerald B. Bashaw                         Director, Chairman of the Board,          November 26, 1996
--------------------------                 Secretary
Gerald B. Bashaw                           


s/James D. Goldenetz                       Director                                  November 26, 1996
--------------------------                                                                                  
James D. Goldenetz


s/James M. Phillips, Jr.                   Director                                  November 26, 1996
--------------------------                                                                              
James M. Phillips, Jr.


s/Robert W. Campbell                       Director                                  November 26, 1996
--------------------------                                                                                  
Robert W. Campbell


s/Myron A. Wick III                        Director                                  November 26, 1996
--------------------------                                                                                   
Myron A. Wick III


s/Charles C. McGettigan                    Director                                  November 26, 1996
--------------------------                                                                               
Charles C. McGettigan


s/Michael G. Rhodes                        Chief Financial Officer                   November 26, 1996
--------------------------                                                                                   
Michael G. Rhodes
</TABLE>





                                      II-4