EXHIBIT 5

                     LEBOEUF, LAMB, GREENE & MACRAE, L.L.P.
       A LIMITED LIABILITY PARTNERSHIP INCLUDING PROFESSIONAL CORPORATIONS
                               260 FRANKLIN STREET
                                BOSTON, MA 02110



                                                   July 26, 2000


Unitil Corporation
6 Liberty Lane West
Hampton, NH 03842-1720

Ladies and Gentlemen:

     We have acted as counsel to Unitil Corporation, a New Hampshire corporation
(the  "Company"),  in connection with the filing of a Registration  Statement by
the Company under the  Securities  Act of 1933, as amended (the "1933 Act"),  on
Form S-8 (the  "Registration  Statement"),  providing  for the  registration  of
150,000 shares (the "Plan Shares") of the Company's  common stock, no par value,
to be issued pursuant to the Company's Tax Deferred  Savings and Investment Plan
(the "Plan").

     In  connection  with this opinion,  we have  examined  originals or copies,
certified or otherwise  identified  to our  satisfaction,  of such  instruments,
certificates, records and documents, and have reviewed such questions of law, as
we have deemed  necessary or appropriate  for purposes of this opinion.  In such
examination, we have assumed the genuineness of all signatures, the authenticity
of all documents  submitted to us as originals,  the  conformity to the original
documents of all documents submitted to us as copies and the authenticity of the
originals  of all  such  latter  documents.  As to any  facts  material  to this
opinion, we have relied upon the aforesaid  instruments,  certificates,  records
and documents and inquiries of Company representatives.







Unitil Corporation
July 26, 2000
Page two


     Based upon the foregoing  examination,  and subject to the  limitations set
forth below,  we are of the opinion that the Plan Shares will be validly issued,
fully paid and nonassessable when:

     (a) the  Registration  Statement  shall have become,  and for so long as it
shall  remain,  effective  for the purpose of the  issuance and sale of the Plan
Shares; and

     (b) the  consideration  therefor provided for in the Plan has been received
by the Company.

     This opinion is rendered  under and limited to the New  Hampshire  Business
Corporation Act (without reference to "blue sky" matters) and the federal law of
the United States.  We consent to the filing of this opinion as Exhibit 5 to the
Registration Statement and in any amendments thereto. In giving such consent, we
do not thereby  concede that we are within the category of persons whose consent
is required under Section 7 of the 1933 Act, or the rules and regulations of the
Securities and Exchange Commission thereunder.

                                     Very truly yours,

                                     /s/ LeBoeuf, Lamb, Greene & MacRae, L.L.P.