UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

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  ¨

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¨ 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

MARVELL TECHNOLOGY GROUP LTD.

(Name of Registrant as Specified In Its Charter)

N/A

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

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¨ 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.

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M59670-P37666

*** Exercise Your Right to Vote ***

Important Notice Regarding the Availability of Proxy Materials for the

Shareholder Meeting to Be Held on June 26, 2013.

MARVELL TECHNOLOGY GROUP LTD.

MARVELL ®

MARVELL TECHNOLOGY GROUP LTD.

CANON’S COURT

22 VICTORIA STREET

HAMILTON HM 12

BERMUDA

Meeting Information

Meeting Type: Annual General Meeting

For holders as of: April 29, 2013

Date: June 26, 2013 Time: 4:00 p.m., PT

Location: Network Meeting Center at Techmart

5201 Great America Parkway

Santa Clara, California 95054

You are receiving this communication because you hold shares in the company named above.

This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side).

We encourage you to access and review all of the important information contained in the proxy materials before voting.

See the reverse side of this notice to obtain proxy materials and voting instructions.

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Before You Vote

How to Access the Proxy Materials

Proxy Materials Available to VIEW or RECEIVE:

NOTICE AND PROXY STATEMENT FORM 10-K SHAREHOLDER LETTER

How to View Online:

Have the information that is printed in the box marked by the arrow XXXX XXXX XXXX (located on the following page) and visit: www.proxyvote.com.

How to Request and Receive a PAPER or E-MAIL Copy:

If you want to receive a paper or e-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request:

1) BY INTERNET: www.proxyvote.com

2) BY TELEPHONE: 1-800-579-1639

3) BY E-MAIL*: sendmaterial@proxyvote.com

* If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow XXXX XXXX XXXX (located on the following page) in the subject line.

Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before June 12, 2013 to facilitate timely delivery.

How To Vote

Please Choose One of the Following Voting Methods

Vote In Person: Many shareholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares.

Vote By Internet: To vote now by Internet, go to www.proxyvote.com. Have the information that is printed in the box marked by the arrow XXXX XXXX XXXX (located on the following page) available and follow the instructions.

Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card.

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Voting Items

AT THE ANNUAL GENERAL MEETING, THE BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” PROPOSALS 1, 2, AND 3.

Annual General Meeting Election of Directors

1. Nominees:

1a. Dr. Sehat Sutardja

1b. Dr. Juergen Gromer

1c. Dr. John G. Kassakian

1d. Arturo Krueger

1e. Dr. Randhir Thakur

2. Advisory vote to approve named executive officer compensation.

3. To re-appoint PricewaterhouseCoopers LLP as our auditors and independent registered public accounting firm, and to authorize the audit committee, acting on behalf of the board of directors, to fix the remuneration of the auditors and independent registered public accounting firm, in both cases for the fiscal year ending February 1, 2014.

In their discretion, the proxies are authorized to vote upon such other business as may properly come before the Annual General Meeting.

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