UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant To Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 8, 2012

Tyco International Ltd.

(Exact name of registrant as specified in its charter)

Freier Platz 10

CH-8200 Schaffhausen, Switzerland

(Address of Principal Executive Offices, including Zip Code)

41-52-633-02-44

(Registrant’s telephone number, including Area Code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions ( see General Instruction A.2. below):

Item 8.01. Other Events.

On May 8, 2012, Tyco International Ltd. (“Tyco”) issued a press release announcing that it has filed preliminary proxy materials with the U.S. Securities and Exchange Commission (the “SEC”) seeking approval by its shareholders for its previously announced plan to spin-off The ADT Corporation (“ADT”) and Tyco Flow Control International Ltd. (“Tyco Flow Control”), the election of two nominees to its board of directors effective upon the completion of the spin-offs and certain related matters. In addition, Tyco announced today its board appointees to The ADT Corporation. A copy of the press release is attached hereto as Exhibit 99.1

In connection with the filing of the preliminary proxy materials, Tyco provided presentation materials related to the progress on the planned separation into three independent companies on its investor relations website. A copy of the presentation materials is attached hereto as Exhibit 99.2.

Forward-Looking Statements

Certain statements contained in this Current Report on Form 8-K relating to Tyco’s intention to spin-off ADT and Tyco Flow Control and its intention to effect a merger between Tyco Flow Control and Pentair, Inc. (“Pentair”) are “forward-looking statements” within the meaning of the U.S. Private Securities Litigation Reform Act of 1995. Such statements are based on management’s current beliefs, assumptions, and available information. Forward-looking statements involve risks, uncertainties, and assumptions. Actual results may differ materially from those expressed in forward-looking statements and none of Tyco, ADT, Tyco Flow Control or Pentair undertakes to update such statements, except as required by law. For further information regarding risks and uncertainties related to Tyco’s businesses, see the “Risk Factors” section of its Annual Report on Form 10-K for the fiscal year ended September 30, 2011 and its Quarterly Report on Form 10-Q for the fiscal quarter ended March 30, 2012 filed with the SEC.

Additional Information

In connection with the proposed spin-off transactions, a preliminary proxy statement for the stockholders of Tyco has been filed with the SEC. Tyco will mail the final proxy statement to its stockholders. BEFORE MAKING ANY VOTING DECISION, TYCO’S STOCKHOLDERS AND INVESTORS ARE URGED TO READ THE PROXY STATEMENT AND OTHER DOCUMENTS FILED WITH THE SEC CAREFULLY AND IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED SPIN-OFF TRANSACTIONS. Investors and security holders may obtain, without charge, a copy of the proxy statement, as well as other relevant documents containing important information about Tyco at the SEC’s website (http://www.sec.gov). You may also read and copy any reports, statements and other information filed by Tyco at the SEC public reference room at 100 F. Street, N.E., Washington DC 20549. Please call the SEC at 1-800-SEC-0330 for further information.

Tyco and its directors, executive officers and other members of its management and employees may be deemed to be participants in the solicitation of proxies from its stockholders in connection with the proposed spin-off transactions. Information concerning the interests of Tyco’s participants in the solicitation is set forth in Tyco’s proxy statements and Annual Reports on Form 10-K, previously filed with the SEC, and in the proxy statement relating to the spin-off transactions.

Item 9.01. Financial Statements and Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.