1



EXHIBIT 5.0 OPINION OF MULDOON MURPHY & AGUGGIA LLP


 2








                                  June 9, 2005



Board of Directors
SI Financial Group, Inc.
803 Main Street
Willimantic, Connecticut 06226

      Re:   SI Financial Group, Inc. 2005 Equity Incentive Plan

Board Members:

      We have been requested by SI Financial Group, Inc., a Federal corporation
(the "Company"), to issue our opinion in connection with the registration of
861,872 shares of the Company's common stock, $.01 par value, to be issued
pursuant to the SI Financial Group, Inc. 2005 Equity Incentive Plan (the "Plan")
as awards of restricted stock or upon the exercise of stock options granted or
to be granted under the Plan. The registration of the shares is being effected
on Form S-8 under the Securities Act of 1933.

      We have made such legal and factual examinations and inquiries as we have
deemed advisable for the purpose of rendering this opinion. In our examination,
we have assumed and have not verified (i) the genuineness of all signatures,
(ii) the authenticity of all documents submitted to us as originals, (iii) the
conformity with the originals of all documents supplied to us as copies, and
(iv) the accuracy and completeness of all corporate records and documents and of
all certificates and statements of fact, in each case given or made available to
us by the Company or its subsidiary.

      Based on the foregoing and limited in all respects to Federal law, it is
our opinion that the shares reserved for issuance under the Plan are duly
authorized and, with respect to shares of Company common stock issuable upon the
exercise of stock options granted or to be granted under the Plan, upon payment
for and issuance of the common stock upon exercise of such stock options, and,
with respect to the awards of restricted stock under the Plan, upon issuance of
such shares of stock in the manner described in the Plan, such shares will be
validly issued, fully paid and nonassessable.

      We note that, although certain portions of the Registration Statement on
Form S-8 (the financial statements and schedules) have been included therein
(through incorporation by reference) on the authority of "experts" within the
meaning of the Securities Act, we are not


 3


Board of Directors
SI Financial Group, Inc.
June 9, 2005
Page 2


experts with respect to any portion of the Registration Statement, including
without limitation, to the financial statements or schedules or the other
financial information or data included therein.

      We hereby consent to the filing of this opinion as an exhibit to the
Company's Registration Statement on Form S-8, and we consent to the use of the
name of our firm under the heading "Interests of Named Experts and Counsel"
therein.


                                    Very truly yours,


                                    /s/ Muldoon Murphy & Aguggia LLP
                                    --------------------------------
                                    MULDOON MURPHY & AGUGGIA LLP