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                                                                     Exhibit 8.1

                          GOODWIN, PROCTER & HOAR LLP
                               COUNSELORS AT LAW
                                 EXCHANGE PLACE
                        BOSTON, MASSACHUSETTS 02109-2881

                                December 4, 1998


Boston Properties, Inc.
8 Arlington Street
Boston, Massachusetts  02116

Ladies and Gentlemen:

     We have acted as counsel to Boston Properties, Inc., a Delaware corporation
(the "Company") in connection with the preparation of a registration statement
(the "Registration Statement") filed with the Securities and Exchange Commission
on Form S-3, as amended through the date hereof, with respect to the issuance of
up to 890,869 shares (the "Redemption Shares") of common stock, par value $.01
per share ("Common Stock"), of the Company, if and to the extent that the
Company elects to issue such shares to acquire common units of limited
partnership interests ("Units") in Boston Properties Limited Partnership, a
Delaware limited partnership (the "Operating Partnership") (the "Offering") that
were originally issued to Kenvic Associates, a New York general partnership
("Kenvic") in connection with the contribution by Kenvic to the Operating
Partnership of property located at 875 Third Avenue on November 21, 1997.  You
have requested our opinion on certain federal income tax matters in connection
with the Offering.

     Capitalized terms not defined herein shall have the same meaning as in the
Registration Statement.

     In rendering the following opinion, we have examined the Amended and
Restated Certificate of Incorporation (the "Articles") and Bylaws of the
Company, and such other records, certificates and documents as we have deemed
necessary or appropriate for purposes of rendering the opinion set forth herein
(collectively, the "Documents"). We have reviewed the investment activities,
operations and governance of the Company and its subsidiaries. We have relied
upon representations of duly appointed officers of the Company and the Operating
Partnership (including without limitation, representations contained in letters
dated as of November 19, 1998 and today's date (the "Officer's Certificates")),
principally relating to the Company's organization and operations. We assume
that each such representation is and will be true, correct and complete and that
all representations that speak in the future, or to the intention, or to the
best of the belief and knowledge of any person(s) or party(ies) are and will be
true, correct and complete as if made without such qualification. Nothing has
come to our attention

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which would cause us to believe that any of such representations are untrue,
incorrect or incomplete. We assume that the Company will be operated in
accordance with the applicable laws and the terms and conditions of applicable
documents. We have also reviewed the Registration Statement, the Amended and
Restated Agreement of Limited Partnership of the Operating Partnership, and such
other documents as we have deemed appropriate. In addition, we have relied upon
certain additional facts and assumptions described below.

     In rendering the opinion set forth herein, we have assumed (i) the
genuineness of all signatures on documents we have examined, (ii) the
authenticity of all documents submitted to us as originals, (iii) the conformity
to the original documents of all documents submitted to us as copies, 
(iv) the conformity of final documents to all documents submitted to us as
drafts, (v) the authority and capacity of the individual or individuals who
executed any such documents on behalf of any person, (vi) the accuracy and
completeness of all records made available to us, and (vii) the factual accuracy
of all representations, warranties and other statements made by all parties. In
addition, we assume that all interests in the Operating Partnership have been
and will be issued in a transaction (or transactions) that are not required to
be registered under the Securities Act of 1933 and that no interest in the
Operating Partnership offered for sale outside the United States would have been
required to be registered under the Securities Act of 1933 if such interest had
been offered for sale within the United States. We have further assumed that
during its short 1997 taxable year ending December 31, 1997 and subsequent
taxable years, the Company has operated and will operate in such a manner that
has made and will make the representations contained in the Officer's
Certificates true for all such years, and that the Company and its subsidiaries
will not make any amendments to its organizational documents after the date of
this opinion that would affect the Company's qualification as a real estate
investment trust for any taxable year. For purposes of our opinion, we have made
no independent investigation of the facts contained in the documents and
assumptions set forth above, the representations set forth in the Officer's
Certificates, or the Registration Statement. No facts have come to our
attention, however, that would cause us to question the accuracy and
completeness of such facts or documents in a material way.

     The discussion and conclusion set forth below are based upon the Code, the
Income Tax Regulations and Procedure and Administration Regulations promulgated
thereunder and existing administrative and judicial interpretation thereof, all
of which are subject to change.  No assurance can therefore be given that the
federal income tax consequences described below will not be altered in the
future.  Based on the documents and assumptions set forth above, the
representations set forth in the Officer's Certificates and provided that the
Company continues to meet the applicable asset composition, source of income,
shareholder diversification, distribution, and other requirements of the Code
necessary for a corporation to qualify as a real estate investment trust, we are
of the opinion that

     (1) Commencing with the Company's initial taxable year ended December 31,
1997, the Company has been operated and organized in conformity with the
requirements for 
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qualification as a "real estate investment trust" under the Code, and its method
of operation, as described in the Officers Certificates, will enable it to
continue to meet the requirements for qualification as a "real estate investment
trust" under the Code and

     (2) The information in the Registration Statement under the captions "Tax
Consequences of Exchanging OP Units for Redemption Shares", "Tax Consequences of
Redemption" and "Certain Federal Income Tax Considerations" to the extent that
it constitutes matters of law or legal conclusions, have been reviewed by us and
is correct in all material respects, and our opinion set forth in such
discussion is confirmed.

     We will not review on a continuing basis the Company's compliance with the
documents or assumptions set forth above, or the representations set forth in
the Officer's Certificates. Accordingly, no assurance can be given that the
actual results of the Company's operations for any given taxable year will
satisfy the requirements for qualification and taxation as a real estate
investment trust under the Code.  The ability of the Company to continue to meet
the requirements for qualification and taxation as a real estate investment
trust will be dependent upon the Company's ability to continue to meet in each
year the applicable asset composition, source of income, shareholder
diversification, distribution, and other requirements of the Code necessary for
a corporation to qualify as a real estate investment trust.  The foregoing
opinions are limited to the federal income tax matters addressed herein, and no
other opinions are rendered with respect to other federal tax matters or to any
issues arising out of the tax laws of any state or locality.  We express no
opinion with respect to the transactions described herein other than those
expressly set forth herein.  You should recognize that our opinion is not
binding on the Internal Revenue Service and that the Internal Revenue Service
may disagree with the opinions contained herein.  Although we believe that our
opinion will be sustained if challenged, there is no guarantee that this will be
the case.  Except as specifically discussed above, the opinion expressed herein
is based upon the laws that currently exist.  Consequently, future changes in
the law may cause the federal income tax treatment of the transactions herein to
be materially and adversely different from that described above.  This opinion
may be relied on solely by you in connection with the Offering.

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement.  We also consent to the references to Goodwin, Procter &
Hoar,  LLP under the caption "Certain Federal Income Tax Considerations" in the
Registration Statement.  In giving this consent, we do not admit that we are in
the category of persons whose consent is required by Section 7 of the Securities
Act of 1933, as amended, or the rules and regulations promulgated thereunder by
the Securities and Exchange Commission.

                                    Very truly yours,


                                    /s/ Goodwin, Procter & Hoar  LLP


                                    Goodwin, Procter & Hoar  LLP
