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)

June 17, 2013

WEYERHAEUSER COMPANY

(Exact name of registrant as specified in charter)

Federal Way, Washington 98063-9777

(Address of principal executive offices)

(253) 924-2345

(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:

ITEM 8.01. OTHER EVENTS.

The consolidated financial statements of Weyerhaeuser Company (the “Company”) and subsidiaries as of December 31, 2012 and 2011, and for each of the years in the three-year period ended December 31, 2012, and management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2012 (collectively, the “Annual Financial Statements”), have been incorporated by reference in the registration statement (No. 333-182403) on Form S-3 of the Company (the “Registration Statement”). The Annual Financial Statements have been audited by KPMG LLP. The consent of KPMG LLP to the incorporation by reference of their audit reports on such Annual Financial Statements in the Registration Statement and to their being referred to under the heading “Experts” in the Registration Statement is attached hereto as Exhibit 23.1.

We have announced that we have signed a definitive stock purchase agreement to acquire Longview Timber LLC and subsidiaries (“Longview”) from affiliates of Brookfield Asset Management for a purchase price of $2.65 billion, which includes the assumption of debt. The consolidated financial statements of Longview as of and for the year ended December 31, 2012 (collectively, the “Longview Annual Financial Statements”) are included herein as Exhibit 99.1. The Longview Annual Financial Statements have been audited by Deloitte & Touche LLP. The consent of Deloitte & Touche LLP to the incorporation by reference of their audit report on such Longview Annual Financial Statements in the Registration Statement and to their being referred to under the heading “Experts” in any prospectus supplement filed under the Registration Statement is attached hereto as Exhibit 23.2.

ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS.

(a) Financial Statements of Business Acquired. In accordance with Item 9.01(a), the audited consolidated financial statements of Longview as of and for the fiscal year ended December 31, 2012 and the notes thereto and the unaudited consolidated financial statements of Longview as of and for the three months ended March 31, 2013 and 2012 are filed in this Report as Exhibits 99.1 and 99.2, respectively.

SPECIAL NOTICE REGARDING FORWARD-LOOKING STATEMENTS

This report contains statements concerning our future results and performance and other matters that are “forward-looking” statements within the meaning of Section 21E of the Securities Exchange Act of 1934.

These statements:

Factors listed in this section—as well as other factors not included—may cause our actual results to differ from our forward-looking statements. There is no guarantee that any of the events anticipated by our forward-looking statements will occur, and, if any of the events occur, there is no guarantee what effect they will have on our operations or financial condition.

We will not update the forward-looking statements contained in any document after the date of such document.

Some forward-looking statements discuss our plans, strategies and intentions. They use words such as “expects”, “may”, “will”, “believes”, “should”, “approximately”, “anticipates”, “estimates” and “plans”. In addition, these words may use the positive or negative or a variation of those terms. We base our forward-looking statements on a number of factors, including the expected effect of the economy, regulations, adverse litigation outcomes and the adequacy of reserves, changes in accounting principles, contributions to pension plans, projected benefit payments, projected tax rates and credits and other related matters.

Major risks and uncertainties—and assumptions that we make—that affect our business and may cause actual results to differ from these forward-looking statements include, but are not limited to:

For additional information regarding forward-looking statements, refer to the reports and other information that we file with the SEC, including our Annual Report on Form 10-K for the fiscal year ended December 31, 2012, our Quarterly Report on Form 10-Q for the quarter ended March 31, 2013 and our Current Report on Form 8-K dated June 17, 2013.

The closing of the acquisition discussed in this report is subject to the receipt of certain third party consents and the satisfaction or waiver of various customary closing conditions. The acquisition may not close within the anticipated time period or or at all.

SIGNATURE

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.

Date: June 17, 2013

EXHIBIT INDEX