UNITED STATES SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE 14A

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION
Proxy Statement Pursuant to Section 14(a) of the Securities
Exchange Act of 1934 (Amendment No. _ )

Filed by the Registrant þ
Filed by a Party other than the Registrant o
Check the appropriate box:

o Preliminary Proxy Statement		o Confidential, for Use of the Commission Only (as
		permitted by Rule 14a-6(e)(2))
o Definitive Proxy Statement
þ Definitive Additional Materials
o Soliciting Material Pursuant to §240.14a-12

THE ADVISORY BOARD COMPANY

(Name of Registrant as Specified in Its Charter)

(Name of Person(s) Filing Proxy Statement if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

þ No fee required.

o Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

		(1)     Title of each class of securities to which transaction applies:
		(2)     Aggregate number of securities to which transaction applies:
		(3)     Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (Set forth the amount on which the filing fee is calculated and state how it was determined):
		(4)     Proposed maximum aggregate value of transaction:
		(5)     Total fee paid:
o		Fee paid previously with preliminary materials.
o		Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the form or schedule and the date of its filing.
		(1)     Amount previously paid:
		(2)     Form, schedule or registration statement no.:
		(3)     Filing party:
		(4)     Date filed:

NOTICE

This notice is being provided with respect to the proxy statement of The Advisory Board Company (the “Company”), as filed with the Securities and Exchange Commission on July 27, 2009 in connection with the Company’s 2009 Annual Meeting of Stockholders (the “Annual Meeting”), to correct the reference to the record date for the Annual Meeting. The record date for the Annual Meeting is July 14, 2009, and only stockholders of record at the close of business on July 14, 2009 are entitled to notice of and to vote at the Annual Meeting and any adjournment or postponement thereof.