<PAGE>   1

       As filed with the Securities and Exchange Commission on May 9, 2001
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                -----------------
                             BANK MUTUAL CORPORATION
             (Exact name of registrant as specified in its charter)

         U.S.A.                                              39-2004336
(State or other jurisdiction of                           (I.R.S. Employer
incorporation or organization)                            Identification No.)

4949 West Brown Deer Road
Milwaukee, Wisconsin                                           53223
(Address of Principal Executive Offices)                     (Zip Code)

                  MUTUAL SAVINGS BANK 2001 STOCK INCENTIVE PLAN
                            (Full title of the plans)

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

                                                             Copy to:
      MICHAEL T. CROWLEY, JR.                          KENNETH V. HALLETT
      Bank Mutual Corporation                          Quarles & Brady LLP
     4949 West Brown Deer Road                      411 East Wisconsin Avenue
    Milwaukee, Wisconsin 53233                     Milwaukee, Wisconsin  53202

                     (Name and address of agent for service)

                                 (414) 354-1500
          (Telephone number, including area code, of agent for service)


                         CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------------
                                                           Proposed                Proposed
                                                           Maximum                 Maximum              Amount of
    Title of Securities           Amount to be          Offering Price            Aggregate           Registration
    to be Registered (1)         Registered (1)         Per Share (1)         Offering Price (2)           Fee
<S>                            <C>                  <C>                     <C>                    <C>
  Common Stock,
  $.01 par value                   1,449,303               $11.575              $16,775,682.25           $4,194

======================================================================================================================
</TABLE>

     (1)  The Plan provides for equitable adjustment of all shares in the event
          of stock splits on dividends, and this registration statement also
          covers any such shares issuable as a result of any future stock splits
          or dividends.

     (2)  Pursuant to Rule 457(h), estimated solely for computing the
          registration fee, based upon the average high and low trading prices
          of Bank Mutual Common Stock on the Nasdaq Stock Market on May 4, 2001.



<PAGE>   2

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

         Information specified in Part I of Form S-8 (Items 1 and 2) will be
sent or given to Plan participants as specified by Rule 428(b)(1) under the
Securities Act of 1933.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents filed by Bank Mutual Corporation (the
"Registrant") (Commission File No. 000-31207) with the Securities and Exchange
Commission pursuant to Section 13 or 15(d) of the Securities Exchange Act of
1934 are incorporated herein by reference:

         -     The Registrant's Annual Report on Form 10-K for the year ended
               December 31, 2000.

         -     The financial statements of First Northern Capital Corp., and the
               pro forma financial statements of the Registrant, including in
               the Registrant's report on Form 8-K dated November 1, 2000, as
               amended December 29, 2000.

         -     Description of the Registrant's common stock contained in the
               Registrant's registration statement on Form 8-A, as amended
               September 20, 2000; and any future amendment or report filed for
               the purpose of updating such description.

         All documents subsequently filed by the registrant or the plans
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to
the filing of a post-effective amendment which indicates that all securities
offered hereby have been sold or which deregisters all securities then remaining
unsold, shall be deemed to be incorporated by reference herein and to be a part
hereof from the date of the 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 hereof to the extent that a statement contained herein or in any
other subsequently filed document which also is or is deemed to be incorporated
by reference herein modifies or supersedes such statement. Any statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part hereof.

ITEM 4.  DESCRIPTION OF SECURITIES.

         Not applicable. See last bullet point in Item 3 above.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Bank Mutual is incorporated under federal law, and, as provided in its
bylaws, indemnification of its directors will be governed by federal law, and
Office of Thrift Supervision ("OTS") regulations thereunder. OTS regulations
define areas for indemnity coverage by federal savings banks and the holding
companies of federal savings banks, such as the registrant, as follows:

         (a) Any person against who any action is brought or threatened because
that person is or was a director or officer of the registrant shall be
indemnified by the registrant, as the case may be, for:


                                      - 2 -

<PAGE>   3

               (1)  Any amount for which such person becomes liable under a
                    judgment in such action; and

               (2)  Reasonable costs and expenses, including reasonable
                    attorney's fees, actually paid or incurred by such person in
                    defending or settling such action, or in enforcing his or
                    her rights to indemnification if the person attains a
                    favorable judgment in such enforcement action, which may be
                    advanced in certain instances.

         (b) Indemnification provided for in subparagraph (a) shall be made to
such officer or director only if the requirements of this paragraph are met:

               (1)  The registrant shall make the indemnification provided by
                    subparagraph (a) in connection with any such action which
                    results in a final judgment on the merits in favor of such
                    officer or director.

               (2)  The registrant shall make the indemnification provided by
                    subparagraph (a) in case of settlement of such action, final
                    judgment against such director or officer or final judgment
                    in favor of such director or officer other than on the
                    merits, if a majority of the disinterested directors of the
                    registrant determines that such a director or officer was
                    acting in good faith within the scope of his or her
                    employment or authority as he or she could reasonable have
                    believed under the circumstances was in the best interest of
                    the registrant or its shareholders.

         (c) As used in this paragraph:

               (1)  "action" means any judicial or administrative proceeding, or
                    threatened proceeding, whether civil, criminal, or
                    otherwise, including any appeal or other proceeding for
                    review;

               (2)  "final judgment" means a judgment. decree, or order which is
                    not appealable and as to which the period for appeal has
                    expired with no appeal taken;

               (3)  "settlement" includes the entry of a judgment by consent or
                    by confession or a plea of guilty or nolo contendere.

         The registrant has a directors and officers liability policy providing
for insurance against certain liabilities incurred by directors and officers of
the registrant while serving in their capacities as such.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

ITEM 8.  EXHIBITS.

         See the Exhibit Index following the Signatures pages in this
Registration Statement, which Exhibit Index is incorporated herein by reference.

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 Securities Act of 1933;

                                     - 3 -

<PAGE>   4

                    (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,
                         represent a fundamental change in the information set
                         forth in the registration statement. Notwithstanding
                         the foregoing, any increase or decrease in volume of
                         securities offered (if the total dollar value of
                         securities offered would not exceed that which was
                         registered) and any deviation from the low or high end
                         of the estimated maximum offering range may be
                         reflected in the form of prospectus filed with the
                         Commission pursuant to Rule 424(b) if, in the
                         aggregate, the changes in volume and price represent no
                         more than a 20% change in the maximum aggregate
                         offering price set forth in the "Calculation of
                         Registration Fee" table in the effective registration
                         statement; and

                   (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 (1)(i) and (1)(ii) of this section 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 with or furnished to the
Commission by the registrant pursuant to Section 13 or Section 15(d) of the
Securities Exchange Act of 1934 that are incorporated by reference in the
registration statement.

               (2)  That, for the purpose of determining any liability under the
                    Securities Act of 1933, 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 of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plans' annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) 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 of 1933 may be permitted to directors, officers and controlling
persons of the Registrant pursuant to the provisions referred to in Item 6 of
this registration statement, 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 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 Act and
will be governed by the final adjudication of such issue.



                                     - 4 -

<PAGE>   5

                                   SIGNATURES

         The registrant. 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 Brown Deer, State of Wisconsin, on May 8, 2001.


                                       BANK MUTUAL CORPORATION
                                       (Registrant)


                                       /s/ Michael T. Crowley, Jr.
                                       ----------------------------------------
                                       By:   Michael T. Crowley, Jr.
                                       Chairman and Chief Executive Officer


                                POWER OF ATTORNEY

         Each person whose signature appears below hereby authorizes Michael T.
Crowley, Jr. and Eugene H. Maurer, Jr., or either of them, as attorneys-in-fact
with full power of substitution, to execute in the name and on behalf of such
person, individually, and in each capacity stated below or otherwise, and to
file, any and all amendments to this registration statement.

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

SIGNATURE AND TITLE

<TABLE>
<S>                                                                <C>
/s/ Michael T. Crowley, Jr.                                        /s/ Marc C. Herr
---------------------------                                        ----------------
Michael T. Crowley, Jr., Chairman and Chief                        Marc C. Herr, Director
Executive Officer (Principal Executive Officer) and
Director

                                                                   /s/ Thomas J. Lopina, Director
                                                                   ------------------------------
/s/  Rick B. Colberg                                               Thomas J. Lopina, Director
--------------------
Rick B. Colberg, Chief Financial Officer                           /s/ Michael D. Meeuwsen
(Principal Financial Officer)                                      -----------------------
                                                                   Michael D. Meeuwsen, Director

/s/  Marlene M. Scholz                                             /s/ William J. Mielke
----------------------                                             ---------------------
Marlene M. Scholz, Senior Vice President                           William J. Mielke, Director
(Principal Accounting Officer)

/s/ Michael T. Crowley, Sr.                                        /s/ Robert B. Olson
---------------------------                                        -------------------
Michael T. Crowley, Sr., Director                                  Robert B. Olson, Director

/s/ Thomas H. Buestrin                                             /s/ David J. Rolfs
----------------------                                             ------------------
Thomas H. Buestrin, Director                                       David J. Rolfs, Director

/s/ Raymond W. Dwyer                                               /s/ J. Gus Swoboda
--------------------                                               ------------------
Raymond W. Dwyer, Jr., Director                                    J. Gus Swoboda, Director
</TABLE>



----------------------
*Each of the above signatures is affixed as of May 8, 2001.


                                     - 5 -

<PAGE>   6

                             Bank Mutual Corporation
                               (the "Registrant")



                                  EXHIBIT INDEX
                                       TO
                         FORM S-8 REGISTRATION STATEMENT


<TABLE>
<S><C>
Exhibit                                                     Incorporated Herein              Filed
Number          Description                                 By Reference To                  Herewith
4.1             Charter of Registrant                       Exhibit 3(i) to the
                                                            Registrant's Form S-1 (No.
                                                            333-39362) as amended ("Form
                                                            S-1")

4.2             Bylaws of the Registrant                    Exhibit 3(ii) to Form S-1

5               Opinion of Quarles & Brady LLP                                               X

23.1            Consent of Ernst & Young LLP                                                 X

23.2            Consent of Wipfli Ullrich Bertelson LLP                                      X

23.3            Consent of Quarles & Brady LLP                                               Contained in
                                                                                             Exhibit 5

24              Power of Attorney                                                            Contained in
                                                                                             Signatures page to
                                                                                             this Registration
                                                                                             Statement

99.1            Text of the Plan                            Exhibit A to the Registrant's
                                                            Definitive Proxy Material for
                                                            2001 Annual Meeting of
                                                            Shareholders
</TABLE>

----------------------
         * The registrant hereby undertakes that it will submit or has submitted
each plan and any amendment thereto to the Internal Revenue Service ("IRS") in a
timely manner, and has made or will make all changes required by the IRS in
order to qualify the plan under section 401 of the Internal Revenue Code.


                                     - 6 -
[{"type": "S-8", "sequence": "1", "filename": "c62162s-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 20828}]
{"company-data": {"conformed-name": "BANK MUTUAL CORP", "cik": "0001123270", "assigned-sic": "6035", "irs-number": "390491685"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-60498", "film-number": "1626655"}, "business-address": {"street1": "4949 W. BROWN DEER RD", "city": "BROWN DEER", "state": "WI", "zip": "53223", "phone": "4143626113"}, "mail-address": {"street1": "4949 W. BROWN DEER RD", "city": "BROWN DEER", "state": "WI", "zip": "53223"}}
1

       As filed with the Securities and Exchange Commission on May 9, 2001
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                -----------------
                             BANK MUTUAL CORPORATION
             (Exact name of registrant as specified in its charter)

         U.S.A.                                              39-2004336
(State or other jurisdiction of                           (I.R.S. Employer
incorporation or organization)                            Identification No.)

4949 West Brown Deer Road
Milwaukee, Wisconsin                                           53223
(Address of Principal Executive Offices)                     (Zip Code)

                  MUTUAL SAVINGS BANK 2001 STOCK INCENTIVE PLAN
                            (Full title of the plans)

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

                                                             Copy to:
      MICHAEL T. CROWLEY, JR.                          KENNETH V. HALLETT
      Bank Mutual Corporation                          Quarles & Brady LLP
     4949 West Brown Deer Road                      411 East Wisconsin Avenue
    Milwaukee, Wisconsin 53233                     Milwaukee, Wisconsin  53202

                     (Name and address of agent for service)

                                 (414) 354-1500
          (Telephone number, including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE
----------------------------------------------------------------------------------------------------------------------
                                                           Proposed                Proposed
                                                           Maximum                 Maximum              Amount of
    Title of Securities           Amount to be          Offering Price            Aggregate           Registration
    to be Registered (1)         Registered (1)         Per Share (1)         Offering Price (2)           Fee
Common Stock,
  $.01 par value                   1,449,303               $11.575              $16,775,682.25           $4,194

======================================================================================================================
(1)  The Plan provides for equitable adjustment of all shares in the event
          of stock splits on dividends, and this registration statement also
          covers any such shares issuable as a result of any future stock splits
          or dividends.

     (2)  Pursuant to Rule 457(h), estimated solely for computing the
          registration fee, based upon the average high and low trading prices
          of Bank Mutual Common Stock on the Nasdaq Stock Market on May 4, 2001.
2

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

         Information specified in Part I of Form S-8 (Items 1 and 2) will be
sent or given to Plan participants as specified by Rule 428(b)(1) under the
Securities Act of 1933.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents filed by Bank Mutual Corporation (the
"Registrant") (Commission File No. 000-31207) with the Securities and Exchange
Commission pursuant to Section 13 or 15(d) of the Securities Exchange Act of
1934 are incorporated herein by reference:

         -     The Registrant's Annual Report on Form 10-K for the year ended
               December 31, 2000.

         -     The financial statements of First Northern Capital Corp., and the
               pro forma financial statements of the Registrant, including in
               the Registrant's report on Form 8-K dated November 1, 2000, as
               amended December 29, 2000.

         -     Description of the Registrant's common stock contained in the
               Registrant's registration statement on Form 8-A, as amended
               September 20, 2000; and any future amendment or report filed for
               the purpose of updating such description.

         All documents subsequently filed by the registrant or the plans
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to
the filing of a post-effective amendment which indicates that all securities
offered hereby have been sold or which deregisters all securities then remaining
unsold, shall be deemed to be incorporated by reference herein and to be a part
hereof from the date of the 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 hereof to the extent that a statement contained herein or in any
other subsequently filed document which also is or is deemed to be incorporated
by reference herein modifies or supersedes such statement. Any statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part hereof.

ITEM 4.  DESCRIPTION OF SECURITIES.

         Not applicable. See last bullet point in Item 3 above.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Bank Mutual is incorporated under federal law, and, as provided in its
bylaws, indemnification of its directors will be governed by federal law, and
Office of Thrift Supervision ("OTS") regulations thereunder. OTS regulations
define areas for indemnity coverage by federal savings banks and the holding
companies of federal savings banks, such as the registrant, as follows:

         (a) Any person against who any action is brought or threatened because
that person is or was a director or officer of the registrant shall be
indemnified by the registrant, as the case may be, for:

                                      - 2 -
3

               (1)  Any amount for which such person becomes liable under a
                    judgment in such action; and

               (2)  Reasonable costs and expenses, including reasonable
                    attorney's fees, actually paid or incurred by such person in
                    defending or settling such action, or in enforcing his or
                    her rights to indemnification if the person attains a
                    favorable judgment in such enforcement action, which may be
                    advanced in certain instances.

         (b) Indemnification provided for in subparagraph (a) shall be made to
such officer or director only if the requirements of this paragraph are met:

               (1)  The registrant shall make the indemnification provided by
                    subparagraph (a) in connection with any such action which
                    results in a final judgment on the merits in favor of such
                    officer or director.

               (2)  The registrant shall make the indemnification provided by
                    subparagraph (a) in case of settlement of such action, final
                    judgment against such director or officer or final judgment
                    in favor of such director or officer other than on the
                    merits, if a majority of the disinterested directors of the
                    registrant determines that such a director or officer was
                    acting in good faith within the scope of his or her
                    employment or authority as he or she could reasonable have
                    believed under the circumstances was in the best interest of
                    the registrant or its shareholders.

         (c) As used in this paragraph:

               (1)  "action" means any judicial or administrative proceeding, or
                    threatened proceeding, whether civil, criminal, or
                    otherwise, including any appeal or other proceeding for
                    review;

               (2)  "final judgment" means a judgment. decree, or order which is
                    not appealable and as to which the period for appeal has
                    expired with no appeal taken;

               (3)  "settlement" includes the entry of a judgment by consent or
                    by confession or a plea of guilty or nolo contendere.

         The registrant has a directors and officers liability policy providing
for insurance against certain liabilities incurred by directors and officers of
the registrant while serving in their capacities as such.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

ITEM 8.  EXHIBITS.

         See the Exhibit Index following the Signatures pages in this
Registration Statement, which Exhibit Index is incorporated herein by reference.

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 Securities Act of 1933;

                                     - 3 -
4

                    (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,
                         represent a fundamental change in the information set
                         forth in the registration statement. Notwithstanding
                         the foregoing, any increase or decrease in volume of
                         securities offered (if the total dollar value of
                         securities offered would not exceed that which was
                         registered) and any deviation from the low or high end
                         of the estimated maximum offering range may be
                         reflected in the form of prospectus filed with the
                         Commission pursuant to Rule 424(b) if, in the
                         aggregate, the changes in volume and price represent no
                         more than a 20% change in the maximum aggregate
                         offering price set forth in the "Calculation of
                         Registration Fee" table in the effective registration
                         statement; and

                   (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 (1)(i) and (1)(ii) of this section 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 with or furnished to the
Commission by the registrant pursuant to Section 13 or Section 15(d) of the
Securities Exchange Act of 1934 that are incorporated by reference in the
registration statement.

               (2)  That, for the purpose of determining any liability under the
                    Securities Act of 1933, 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 of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plans' annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) 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 of 1933 may be permitted to directors, officers and controlling
persons of the Registrant pursuant to the provisions referred to in Item 6 of
this registration statement, 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 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 Act and
will be governed by the final adjudication of such issue.

                                     - 4 -
5

                                   SIGNATURES

         The registrant. 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 Brown Deer, State of Wisconsin, on May 8, 2001.

                                       BANK MUTUAL CORPORATION
                                       (Registrant)

                                       /s/ Michael T. Crowley, Jr.
                                       ----------------------------------------
                                       By:   Michael T. Crowley, Jr.
                                       Chairman and Chief Executive Officer

                                POWER OF ATTORNEY

         Each person whose signature appears below hereby authorizes Michael T.
Crowley, Jr. and Eugene H. Maurer, Jr., or either of them, as attorneys-in-fact
with full power of substitution, to execute in the name and on behalf of such
person, individually, and in each capacity stated below or otherwise, and to
file, any and all amendments to this registration statement.

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

SIGNATURE AND TITLE
/s/ Michael T. Crowley, Jr.                                        /s/ Marc C. Herr
---------------------------                                        ----------------
Michael T. Crowley, Jr., Chairman and Chief                        Marc C. Herr, Director
Executive Officer (Principal Executive Officer) and
Director

                                                                   /s/ Thomas J. Lopina, Director
                                                                   ------------------------------
/s/  Rick B. Colberg                                               Thomas J. Lopina, Director
--------------------
Rick B. Colberg, Chief Financial Officer                           /s/ Michael D. Meeuwsen
(Principal Financial Officer)                                      -----------------------
                                                                   Michael D. Meeuwsen, Director

/s/  Marlene M. Scholz                                             /s/ William J. Mielke
----------------------                                             ---------------------
Marlene M. Scholz, Senior Vice President                           William J. Mielke, Director
(Principal Accounting Officer)

/s/ Michael T. Crowley, Sr.                                        /s/ Robert B. Olson
---------------------------                                        -------------------
Michael T. Crowley, Sr., Director                                  Robert B. Olson, Director

/s/ Thomas H. Buestrin                                             /s/ David J. Rolfs
----------------------                                             ------------------
Thomas H. Buestrin, Director                                       David J. Rolfs, Director

/s/ Raymond W. Dwyer                                               /s/ J. Gus Swoboda
--------------------                                               ------------------
Raymond W. Dwyer, Jr., Director                                    J. Gus Swoboda, Director
----------------------
*Each of the above signatures is affixed as of May 8, 2001.

                                     - 5 -
6

                             Bank Mutual Corporation
                               (the "Registrant")

                                  EXHIBIT INDEX
                                       TO
                         FORM S-8 REGISTRATION STATEMENT
Exhibit                                                     Incorporated Herein              Filed
Number          Description                                 By Reference To                  Herewith
4.1             Charter of Registrant                       Exhibit 3(i) to the
                                                            Registrant's Form S-1 (No.
                                                            333-39362) as amended ("Form
                                                            S-1")

4.2             Bylaws of the Registrant                    Exhibit 3(ii) to Form S-1

5               Opinion of Quarles & Brady LLP                                               X

23.1            Consent of Ernst & Young LLP                                                 X

23.2            Consent of Wipfli Ullrich Bertelson LLP                                      X

23.3            Consent of Quarles & Brady LLP                                               Contained in
                                                                                             Exhibit 5

24              Power of Attorney                                                            Contained in
                                                                                             Signatures page to
                                                                                             this Registration
                                                                                             Statement

99.1            Text of the Plan                            Exhibit A to the Registrant's
                                                            Definitive Proxy Material for
                                                            2001 Annual Meeting of
                                                            Shareholders
----------------------
         * The registrant hereby undertakes that it will submit or has submitted
each plan and any amendment thereto to the Internal Revenue Service ("IRS") in a
timely manner, and has made or will make all changes required by the IRS in
order to qualify the plan under section 401 of the Internal Revenue Code.

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