Boston Properties (BXP) S-3ASRAutomatic shelf registration

Exhibit 5.1

[Goodwin Procter LLP Letterhead]

May 22, 2020

Boston Properties, Inc.

Prudential Center

800 Boylston Street, Suite 1900

Boston, MA 02199

Re:    Securities Being Registered under Registration Statement on FormS-3

We have acted as counsel to you in connection with your filing of a Registration Statement on FormS-3ASR (as amended or supplemented, the “Registration Statement”) filed as of the date hereof with the Securities and Exchange Commission pursuant to the Securities Act of 1933, as amended (the “Securities Act”), relating to the registration by Boston Properties, Inc., a Delaware corporation (the “Company”), of 1,265,000 shares (the “Shares”) of the Company’s common stock, par value $0.01 per share (“Common Stock”), that may be issued by the Company pursuant to the Company’s Dividend Reinvestment and Stock Purchase Plan (the “Plan”).

We have reviewed such documents and made such examination of law as we have deemed appropriate to give the opinions set forth below. We have relied, without independent verification, on certificates of public officials and, as to matters of fact material to the opinions set forth below, on certificates of officers of the Company. For purposes of the opinion set forth below, we have assumed that no event occurs that causes the number of authorized shares of Common Stock available for issuance by the Company to be less than the number of then unissued Shares.

The opinion set forth below is limited to the Delaware General Corporation Law.

Based on the foregoing, we are of the opinion that the Shares have been duly authorized and, upon issuance and delivery against payment therefor in accordance with the terms of the Plan, will be validly issued, fully paid and nonassessable.

We hereby consent to the inclusion of this opinion as Exhibit 5.1 to the Registration Statement and to the references to our firm under the caption “Legal Matters” in the Registration Statement. In giving our consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations thereunder.