Mattel, Inc.

Item 1.01 Entry into a Material Definitive Agreement. On November 5, 2025, Mattel, Inc. (“Mattel” or the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with BofA Securities, Inc., Citigroup Global Markets Inc., Wells Fargo Securities, LLC and Goldman Sachs & Co. LLC, as representatives of the several underwriters named therein (the “Underwriters”), in connection with the Company’s previously announced underwritten public offering (the “Offering”) of $600,000,000 aggregate principal amount of 5.000% Senior Notes due 2030 (the “Notes”). The Offering is expected to close on or about November 17, 2025, subject to the satisfaction of customary closing conditions. The Offering was made pursuant to a shelf registration statement on Form S-3 filed by the Company with the Securities and Exchange Commission (the “SEC”) and became automatically effective upon filing on October 30, 2025, and a preliminary prospectus supplement and accompanying prospectus relating to and describing the terms of the Offering was filed with the SEC and a final prospectus supplement related to the Offering will be filed with the SEC. The Underwriting Agreement includes customary representations, warranties, covenants, and closing conditions. It also provides for customary indemnification by the Company and the Underwriters against certain liabilities, including for liabilities under the Securities Act of 1933, as amended, and customary contribution provisions in respect of those liabilities. The Company intends to use the net proceeds from the Offering, together with cash on hand, to redeem all of the Company’s outstanding 3.375% Senior Notes due 2026, and pay related fees and expenses. A copy of the Underwriting Agreement is attached as Exhibit 1.1 to this Current Report on Form 8-K and is incorporated into this Item 1.01 by reference. The above description of the material terms of the Underwriting Agreement does not purport to be complete and is qualified in its entirety by reference to such Exhibit.

Item 8.01. Other Events. On November 5, 2025, the Company issued a press release relating to the pricing of the Offering contemplated by the Underwriting Agreement. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated into this Item 8.01 by reference. Section 9 - Financial Statements and Exhibits