Exhibit 5.1

                     [LETTERHEAD OF THACHER PROFFITT & WOOD]

                                [FORM OF OPINION]


                                                           June __, 1999


Westborough Financial Services, Inc.
c/o Westborough Savings Bank
100 E. Main Street
Westborough, Massachusetts 01581

           Re:    Westborough Financial Services, Inc.
                  ------------------------------------

Ladies and Gentlemen:

      We have acted as special counsel to Westborough Financial Services, Inc.,
a Massachusetts-chartered corporation (the "Company"), in connection with the
proposed registration under the Securities Act of 1933, as amended, by the
Company of an aggregate of 925,750 shares of Common Stock, $0.01 par value per
share, of the Company (the "Shares"), and the related preparation and filing by
the Company with the Securities and Exchange Commission of a Registration
Statement on Form SB-2 (the "Registration Statement") pursuant to the Plan of
Reorganization from Mutual Savings Bank to Mutual Holding Company and Stock
Issuance Plan of Westborough Savings Bank (the "Plan"). In rendering the opinion
set forth below, we do not express any opinion concerning law other than the
federal law of the United States.

      We have examined originals or copies, certified or otherwise identified,
of such documents, corporate records and other instruments, and have examined
such matters of law, as we have deemed necessary or advisable for purposes of
rendering the opinion set forth below. As to matters of fact, we have examined
and relied upon the representations of the Company contained in the Registration
Statement and, where we have deemed appropriate, representations or certificates
of officers of the Company or public officials. We have assumed the authenticity
of all documents submitted to us as originals, the genuineness of all
signatures, the legal capacity of natural persons and the conformity to the
originals of all documents submitted to us as copies. In making our examination
of any documents, we have assumed that all parties, other than the Company, had
the corporate power and authority to enter into and perform all obligations
thereunder, and, as to such parties, we have also assumed the due authorization
by all requisite action, the due execution and delivery of such documents, and
the validity and binding effect and enforceability thereof.


Westborough Financial Services, Inc.
June __, 1999                                                            Page 2.


      Based on the foregoing, we are of the opinion that the Shares have been
duly authorized and, when issued and exchanged as contemplated in the
Registration Statement and the Plan, will be validly issued and outstanding,
fully paid and non-assessable.

      In rendering the opinion set forth above, we have not passed upon and do
not purport to pass upon the application of securities or "blue-sky" laws of any
jurisdiction (except federal securities laws).

      This opinion is given solely for the benefit of the Company and investors
who purchase shares of common stock of the Company pursuant to the Registration
Statement, and may not be relied upon by any other person or entity, nor quoted
in whole or in part, or otherwise referred to in any document without our
express written consent.

      We consent to the filing of this opinion as an Exhibit to the Registration
Statement and to the reference to our name in the Prospectus contained in the
Registration Statement under the heading "Legal and Tax Opinions."


                                          Very truly yours,

                                          THACHER PROFFITT & WOOD


                                          By:
                                             -------------------------
                                             Richard A. Schaberg