<PAGE>   1

      As filed with the Securities and Exchange Commission on September 18, 1996
                                                  Registration No. 33-__________
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

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

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

                                  XIRCOM, INC.
               (Exact name of issuer as specified in its charter)

         CALIFORNIA                                  95-4221884
- -----------------------------------       ----------------------------------
   (STATE OF INCORPORATION)                (IRS EMPLOYER IDENTIFICATION NO.)

                          2300 Corporate Center Drive
                        Thousand Oaks, California 91320
                    (Address of Principal Executive Offices)

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

                             1992 STOCK OPTION PLAN
                            (Full title of the plan)

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

                              Steven F. DeGennaro
                            Chief Financial Officer
                                  XIRCOM, INC.
                          2300 Corporate Center Drive
                        Thousand Oaks, California 91320
                    (Name and address of agent for service)
                                 (805) 376-9300
         (Telephone number, including area code, of agent for service)

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

                                    Copy to:
                             Howard S. Zeprun, Esq.
                        WILSON SONSINI GOODRICH & ROSATI
                            Professional Corporation
                               650 Page Mill Road
                          Palo Alto, California 94304
                           Telephone:  (415) 493-9300

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
=================================================================================================================
       Title of                                                                                  
   Securities to be       Amount to          Proposed Maximum            Proposed Maximum           Amount of
      Registered        be Registered    Offering Price Per Share    Aggregate Offering Price    Registration Fee
==================================================================================================================
 <S>                    <C>              <C>                         <C>                         <C>
 Common Stock,
 $0.001 par value

   Upon exercise of     700,000 shs.             $14.25                     $9,975,000               $3,439.00
   options under
   1992 Stock
   Option Plan

 TOTAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .         $3,439.00
</TABLE>

- --------------------
(1)  Estimated in accordance with Rule 457 solely for the purpose of 
     calculating the registration fee on the basis of the average between the
     high and low price, which average was $14.25 as reported on the Nasdaq
     National Market on September 12, 1996.


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


<PAGE>   2
                                  XIRCOM, INC.
                       REGISTRATION STATEMENT ON FORM S-8

                                    PART II

                 INFORMATION REQUIRED IN REGISTRATION STATEMENT


ITEM 3.   INCORPORATION OF DOCUMENTS BY REFERENCE.
          ---------------------------------------
          
     There are hereby incorporated by reference in this Registration Statement
the following documents and information heretofore filed with the Securities
and Exchange Commission:

     1.   The contents of the Registration Statement on Form S-8 file number
33-49170 filed by the Company with the Securities and Exchange Commission on
July 2, 1992.

     2.   The Company's Annual Report on Form 10-K for the year ended September
30, 1995, filed pursuant to Section 13 of the Securities Exchange Act of 1934,
as amended (the "Exchange Act").

     3.   The Company's Quarterly Reports on Form 10-Q for the quarters ending
December 31, 1995, March 31, 1996 and June 30, 1996 filed pursuant to Section
13 of the Exchange Act.

     4.   The description of the Company's Common Stock contained in the
Company's Registration Statement on Form 8-A dated February 11, 1992, filed
pursuant to Section 12 of the Exchange Act, including any amendment or report
filed for the purpose of updating such description.

     All documents filed by the Company pursuant to Sections 13(a), 13(c), 14
and 15(d) of the Exchange Act on or after the date of this Registration
Statement and prior to the filing of a post-effective amendment which indicates
that all securities offered have been sold or which deregisters all securities
then remaining unsold shall be deemed to be incorporated by reference in this
Registration Statement and to be part hereof from the date of filing of such
documents.





                                      II-1
<PAGE>   3
ITEM 8.  EXHIBITS.
         --------
         
<TABLE>
<CAPTION>
         Exhibit
         Number           Description
         -------          -----------
         <S>              <C>
         4.1              1992 Stock Option Plan, as amended, together with form of option agreement thereunder.

         5.1              Opinion of counsel as to legality of securities being registered.

         23.1             Consent of Ernst & Young, LLP, independent auditors.

         24.2             Consent of counsel (contained in Exhibit 5.1).

         25.1             Power of Attorney (see page II-4).
</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 to
include any material information with respect to the plan of distribution not
previously disclosed in the registration statement or any material change to
such information in the registration statement.

                 (2)      That, for the purpose of determining any liability
under the Securities Act of 1933, as amended (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.

         C.      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





                                      II-2
<PAGE>   4
provisions, or otherwise, the registrant has been advised that in the opinion
of the Securities and Exchange Commission such indemnification is against
public policy as expressed in the Securities Act and is, therefore,
unenforceable.  In the event that a claim for indemnification against such
liabilities (other than the payment by the registrant of expenses incurred or
paid by a director, officer or controlling person of the registrant in 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>   5
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act that 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 Thousand Oaks, State of California, on September 18,
1996.

                                         XIRCOM, INC.

                                         By: /s/ DIRK I. GATES             
                                             ----------------------------------
                                             Dirk I. Gates, Chairman, President 
                                             and Chief Executive Officer


                               POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Dirk I. Gates and Steven F. DeGennaro,
jointly and severally, his attorneys-in-fact, each with the power of
substitution, for him in any and all capacities, to sign any amendments to this
Registration Statement on Form S-8 and to file the same, with exhibits thereto
and other documents in connection therewith, with the Securities and Exchange
Commission, hereby ratifying and confirming all that each of said
attorneys-in-fact, or his substitution or substitutes, may do or cause to be
done by virtue hereof.
         Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed by the following persons in the capacities and on the
dates indicated.

<TABLE>
<CAPTION>
          Signature                                        Title                                    Date
- ---------------------------------          -----------------------------------------         ------------------
 <S>                                       <C>                                               <C>
 /s/ DIRK I. GATES                         President and Chief Executive Officer and         September 18, 1996
 --------------------------------          Director (Principal Executive Officer)
 (Dirk I. Gates)                           

 /s/ STEVEN F. DEGENNARO                   Vice President, Finance and Chief Financial       September 18, 1996
 --------------------------------          Officer (Principal Accounting Officer)
 (Steven F. DeGennaro)                     
                                           
 /s/ MICHAEL F. G. ASHBY                   Director                                          September 18, 1996
 --------------------------------                                                                                    
 (Michael F. G. Ashby)

 /s/ GARY J. BOWEN                         Director                                          September 18, 1996
 --------------------------------                                                                                     
 (Gary J. Bowen)

 /s/ KENNETH J. BIBA                       Director                                          September 18, 1996
 --------------------------------                                                                                   
 (Kenneth J. Biba)

 /s/ J. KIRK MATHEWS                       Director                                          September 18, 1996
 --------------------------------                                                                                  
 (J. Kirk Mathews)

 /s/ WILLIAM J. SCHROEDER                  Director                                          September 18, 1996
 --------------------------------                                                                                      
 (William J. Schroeder)

 /s/ DELBERT W. YOCAM                      Director                                          September 18, 1996
 --------------------------------                                                                                          
 (Delbert W. Yocam)
</TABLE>

                                      II-4





<PAGE>   6
                               INDEX TO EXHIBITS


<TABLE>
<CAPTION>
                                                                                               SEQUENTIALLY
    EXHIBIT                                                                                      NUMBERED
    NUMBER                             DESCRIPTION                                                 PAGE
   ---------    ----------------------------------------------------------------            -------------------
 <S>            <C>
      4.1       1992 Stock Option Plan, as amended, together with form of option
                agreement thereunder


      5.1       Opinion of counsel as to legality of securities being registered

     23.1       Consent of Ernst & Young, LLP, Independent Auditors

     24.2(1)    Consent of Counsel


     25.1(2)    Power of Attorney
</TABLE>

- -------------------
(1)  Contained in Exhibit 5.1.
(2)  See page II-4
[{"type": "S-8", "sequence": "1", "description": "FORM S-8 REGISTRATION STATEMENT", "secsgml_size_bytes": 14146}]
{"company-data": {"conformed-name": "XIRCOM INC", "cik": "0000883905", "assigned-sic": "3576", "irs-number": "954221884", "state-of-incorporation": "CA", "fiscal-year-end": "0930"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-12225", "film-number": "96631688"}, "business-address": {"street1": "2300 CORPORATE CENTER DRIVE", "city": "THOUSAND OAKS", "state": "CA", "zip": "91320", "phone": "8053769300"}, "mail-address": {"street1": "2300 CORPORATE CENTER DRIVE", "city": "THOUSAND OAKS", "state": "CA", "zip": "91320"}}
1

      As filed with the Securities and Exchange Commission on September 18, 1996
                                                  Registration No. 33-__________
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

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

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

                                  XIRCOM, INC.
               (Exact name of issuer as specified in its charter)

         CALIFORNIA                                  95-4221884
- -----------------------------------       ----------------------------------
   (STATE OF INCORPORATION)                (IRS EMPLOYER IDENTIFICATION NO.)

                          2300 Corporate Center Drive
                        Thousand Oaks, California 91320
                    (Address of Principal Executive Offices)

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

                             1992 STOCK OPTION PLAN
                            (Full title of the plan)

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

                              Steven F. DeGennaro
                            Chief Financial Officer
                                  XIRCOM, INC.
                          2300 Corporate Center Drive
                        Thousand Oaks, California 91320
                    (Name and address of agent for service)
                                 (805) 376-9300
         (Telephone number, including area code, of agent for service)

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

                                    Copy to:
                             Howard S. Zeprun, Esq.
                        WILSON SONSINI GOODRICH & ROSATI
                            Professional Corporation
                               650 Page Mill Road
                          Palo Alto, California 94304
                           Telephone:  (415) 493-9300

                        CALCULATION OF REGISTRATION FEE
=================================================================================================================
       Title of                                                                                  
   Securities to be       Amount to          Proposed Maximum            Proposed Maximum           Amount of
      Registered        be Registered    Offering Price Per Share    Aggregate Offering Price    Registration Fee
==================================================================================================================
Common Stock,
 $0.001 par value

   Upon exercise of     700,000 shs.             $14.25                     $9,975,000               $3,439.00
   options under
   1992 Stock
   Option Plan

 TOTAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .         $3,439.00
- --------------------
(1)  Estimated in accordance with Rule 457 solely for the purpose of 
     calculating the registration fee on the basis of the average between the
     high and low price, which average was $14.25 as reported on the Nasdaq
     National Market on September 12, 1996.

================================================================================
2
                                  XIRCOM, INC.
                       REGISTRATION STATEMENT ON FORM S-8

                                    PART II

                 INFORMATION REQUIRED IN REGISTRATION STATEMENT

ITEM 3.   INCORPORATION OF DOCUMENTS BY REFERENCE.
          ---------------------------------------
          
     There are hereby incorporated by reference in this Registration Statement
the following documents and information heretofore filed with the Securities
and Exchange Commission:

     1.   The contents of the Registration Statement on Form S-8 file number
33-49170 filed by the Company with the Securities and Exchange Commission on
July 2, 1992.

     2.   The Company's Annual Report on Form 10-K for the year ended September
30, 1995, filed pursuant to Section 13 of the Securities Exchange Act of 1934,
as amended (the "Exchange Act").

     3.   The Company's Quarterly Reports on Form 10-Q for the quarters ending
December 31, 1995, March 31, 1996 and June 30, 1996 filed pursuant to Section
13 of the Exchange Act.

     4.   The description of the Company's Common Stock contained in the
Company's Registration Statement on Form 8-A dated February 11, 1992, filed
pursuant to Section 12 of the Exchange Act, including any amendment or report
filed for the purpose of updating such description.

     All documents filed by the Company pursuant to Sections 13(a), 13(c), 14
and 15(d) of the Exchange Act on or after the date of this Registration
Statement and prior to the filing of a post-effective amendment which indicates
that all securities offered have been sold or which deregisters all securities
then remaining unsold shall be deemed to be incorporated by reference in this
Registration Statement and to be part hereof from the date of filing of such
documents.

                                      II-1
3
ITEM 8.  EXHIBITS.
         --------
Exhibit
         Number           Description
         -------          -----------
4.1              1992 Stock Option Plan, as amended, together with form of option agreement thereunder.

         5.1              Opinion of counsel as to legality of securities being registered.

         23.1             Consent of Ernst & Young, LLP, independent auditors.

         24.2             Consent of counsel (contained in Exhibit 5.1).

         25.1             Power of Attorney (see page II-4).
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 to
include any material information with respect to the plan of distribution not
previously disclosed in the registration statement or any material change to
such information in the registration statement.

                 (2)      That, for the purpose of determining any liability
under the Securities Act of 1933, as amended (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.

         C.      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

                                      II-2
4
provisions, or otherwise, the registrant has been advised that in the opinion
of the Securities and Exchange Commission such indemnification is against
public policy as expressed in the Securities Act and is, therefore,
unenforceable.  In the event that a claim for indemnification against such
liabilities (other than the payment by the registrant of expenses incurred or
paid by a director, officer or controlling person of the registrant in 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
5
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act that 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 Thousand Oaks, State of California, on September 18,
1996.

                                         XIRCOM, INC.

                                         By: /s/ DIRK I. GATES             
                                             ----------------------------------
                                             Dirk I. Gates, Chairman, President 
                                             and Chief Executive Officer

                               POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Dirk I. Gates and Steven F. DeGennaro,
jointly and severally, his attorneys-in-fact, each with the power of
substitution, for him in any and all capacities, to sign any amendments to this
Registration Statement on Form S-8 and to file the same, with exhibits thereto
and other documents in connection therewith, with the Securities and Exchange
Commission, hereby ratifying and confirming all that each of said
attorneys-in-fact, or his substitution or substitutes, may do or cause to be
done by virtue hereof.
         Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed by the following persons in the capacities and on the
dates indicated.
Signature                                        Title                                    Date
- ---------------------------------          -----------------------------------------         ------------------
/s/ DIRK I. GATES                         President and Chief Executive Officer and         September 18, 1996
 --------------------------------          Director (Principal Executive Officer)
 (Dirk I. Gates)                           

 /s/ STEVEN F. DEGENNARO                   Vice President, Finance and Chief Financial       September 18, 1996
 --------------------------------          Officer (Principal Accounting Officer)
 (Steven F. DeGennaro)                     
                                           
 /s/ MICHAEL F. G. ASHBY                   Director                                          September 18, 1996
 --------------------------------                                                                                    
 (Michael F. G. Ashby)

 /s/ GARY J. BOWEN                         Director                                          September 18, 1996
 --------------------------------                                                                                     
 (Gary J. Bowen)

 /s/ KENNETH J. BIBA                       Director                                          September 18, 1996
 --------------------------------                                                                                   
 (Kenneth J. Biba)

 /s/ J. KIRK MATHEWS                       Director                                          September 18, 1996
 --------------------------------                                                                                  
 (J. Kirk Mathews)

 /s/ WILLIAM J. SCHROEDER                  Director                                          September 18, 1996
 --------------------------------                                                                                      
 (William J. Schroeder)

 /s/ DELBERT W. YOCAM                      Director                                          September 18, 1996
 --------------------------------                                                                                          
 (Delbert W. Yocam)
II-4
6
                               INDEX TO EXHIBITS
SEQUENTIALLY
    EXHIBIT                                                                                      NUMBERED
    NUMBER                             DESCRIPTION                                                 PAGE
   ---------    ----------------------------------------------------------------            -------------------
4.1       1992 Stock Option Plan, as amended, together with form of option
                agreement thereunder

      5.1       Opinion of counsel as to legality of securities being registered

     23.1       Consent of Ernst & Young, LLP, Independent Auditors

     24.2(1)    Consent of Counsel

     25.1(2)    Power of Attorney
- -------------------
(1)  Contained in Exhibit 5.1.
(2)  See page II-4