SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 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): September 3, 2013

LYONDELLBASELL INDUSTRIES N.V.

(Exact Name of Registrant as Specified in Charter)

(Addresses of principal executive offices)

(Registrant’s telephone numbers, including area codes)

(Former Name or Former Address, if Changed Since Last Report)

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.

On September 3, 2013, LyondellBasell Industries N.V. (the “Company”) entered into an Underwriting Agreement (the “Underwriting Agreement”) with Citigroup Global Markets Inc. (the “Underwriter”) and the selling shareholders listed on Schedule A-1 thereto (the “Selling Shareholders”), relating to the underwritten offering and sale by the Selling Shareholders of 16,000,000 ordinary shares (the “Shares”), par value €0.04 per share, of the Company (the “Offering”). The Underwriter agreed to purchase the Shares from the Selling Shareholders at a price of $69.43 per share. The Underwriter may offer the Shares from time to time in transactions on the New York Stock Exchange, in the over-the-counter market, through negotiated transactions or otherwise at market prices. The Underwriting Agreement contains customary representations, warranties and covenants of the Company and the Selling Shareholders, conditions to closing, indemnification obligations of the Company, the Selling Shareholders and the Underwriters, and termination and other customary provisions. The foregoing description of the Underwriting Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the document which is attached as Exhibit 1.1 to this Current Report on Form 8-K and incorporated by reference herein. The Offering is expected to close on September 9, 2013.

The Offering was made pursuant to a shelf registration statement the Company filed with the Securities and Exchange Commission that became effective on June 17, 2013 (Registration No. 333-189375). A copy of the opinion regarding the legality of the Shares is filed as Exhibit 5.1 to this Current Report on Form 8-K.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

SIGNATURES

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

Exhibit Index