SCHEDULE 14-A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

Filed by the Registrant  x                             Filed by a Party other than the Registrant  ¨

Check the appropriate box:

¨ Preliminary Proxy Statement

¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

¨ Definitive Proxy Statement

x Definitive Additional Materials

¨ Soliciting Material Pursuant to § 240.14a-12

Harvard Illinois Bancorp, Inc.

(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):

x No fee required.

¨ Fee computed on table below per Exchange Act Rules 14a-6(i)(4) 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:

¨ 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:

On April 5, 2012, the Company mailed the following notice to its shareholders of record:

April 5, 2012

This mailing contains the WHITE Ballot, Proxy Statement and Return envelope for the Harvard Illinois Bancorp, Inc. Annual Meeting to be held at the Harvard Police Station, 201 West Front St., 2^nd Floor, Harvard Illinois, at 8:00 a.m. Illinois time on May 24, 2012.

Also today, under separate cover, you received the Harvard Illinois Bancorp, Inc. Form 10-K, the Annual Report pursuant to section 13 or 15(d) of the Securities Exchange Act of 1934, for the fiscal year ended December 31, 2011.

Please vote the WHITE ballot mailed in either mailing, insert into the return envelope in either mailing, and return IMMEDIATELY.

Thank you for your diligent attention to this matter.