EXHIBIT 5.1

EXHIBIT 5.1


Goodwin Procter LLP
Counsellors at Law
Exchange Place
Boston, MA 02109
T: 617.570.1000
F: 617.523.1231



March 11, 2003



AvalonBay Communities, Inc.
2900 Eisenhower Avenue, Suite 300
Alexandria, VA 22314

Re: LEGALITY OF SECURITIES TO BE REGISTERED
UNDER REGISTRATION STATEMENT ON FORM S-3

Ladies and Gentlemen:

This opinion is delivered in our capacity as counsel to AvalonBay
Communities, Inc., a Maryland corporation (the "Company"), in connection with
the Company's registration statement on Form S-3 (the "Registration Statement")
filed with the Securities and Exchange Commission under the Securities Act of
1933, as amended, which relates to the sale from time to time of an
indeterminate amount of debt securities ("Debt Securities"), shares of preferred
stock, par value $.01 per share ("Preferred Stock"), and shares of common stock,
par value $.01 per share ("Common Stock"), or any combination of Debt
Securities, Preferred Stock and Common Stock (collectively, the "Securities"),
having a maximum aggregate public offering price of $750,000,000. The
Registration Statement provides that the Securities may be offered separately or
together, in separate series, in amounts, at prices and on terms to be set forth
in one or more prospectus supplements (each a "Prospectus Supplement") to the
prospectus contained in the Registration Statement.

We have examined the charter of the Company, as amended and on file
with the Maryland State Department of Assessments and Taxation, the bylaws of
the Company, as amended, such records of corporate proceedings of the Company as
we have deemed appropriate for the purposes of this opinion, the Registration
Statement and the exhibits thereto.

Based upon the foregoing, we are of the opinion that (i) when the
Securities are specifically authorized for issuance by the Company's Board of
Directors or an authorized committee thereof (the "Authorizing Resolution"),
(ii) upon receipt by the Company of the full consideration therefor as provided
in the Authorizing Resolution and (iii) upon the issuance of the Securities as
described in the Registration Statement and a Prospectus Supplement that is





consistent with the Authorizing Resolution, the Securities will be legally
issued, fully paid and nonassessable.

We hereby consent to being named as counsel to the Company in the
Registration Statement, to the references therein to our firm under the caption
"Legal Opinions" and to the inclusion of this opinion as an exhibit to the
Registration Statement.


Very truly yours,

/s/ Goodwin Procter LLP

GOODWIN PROCTER LLP