Form 8-A12B THERMO FISHER SCIENTIFIC

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-A

FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES

PURSUANT TO SECTION 12(b) OR 12(g) OF THE

SECURITIES EXCHANGE ACT OF 1934

Thermo Fisher Scientific Inc.

(Exact name of registrant as specified in its charter)

(Exact name of registrant as specified in its charter)

Securities to be registered pursuant to Section 12(b) of the Act:

If this form relates to the registration of a class of securities pursuant to Section 12(b) of the Exchange Act and is effective pursuant to General Instruction A.(c) or (e), check the following box. ☒

If this form relates to the registration of a class of securities pursuant to Section 12(g) of the Exchange Act and is effective pursuant to General Instruction A.(d) or (e), check the following box. ☐

If this form relates to the registration of a class of securities concurrently with a Regulation A offering, check the following box. ☐

Securities Act registration statement or Regulation A offering statement file number to which this form relates (if applicable): 333-285159

Securities to be registered pursuant to Section 12(g) of the Act:  None

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INFORMATION REQUIRED IN REGISTRATION STATEMENT

Thermo Fisher Scientific Inc. (“Thermo Fisher”) and Thermo Fisher Scientific (Finance I) B.V. (“Thermo Fisher International” and together with Thermo Fisher, the “Registrants”) have filed with the Securities and Exchange Commission (the “Commission”) pursuant to Rule 424(b) under the Securities Act of 1933, as amended (the “Securities Act”), a prospectus supplement, dated November 24, 2025 (the “Prospectus Supplement”), and the accompanying prospectus, dated February 24, 2025 (the “Base Prospectus”).  The Prospectus Supplement relates to the offering of €1,000,000,000 aggregate principal amount of Floating Rate Senior Notes due 2027 and €1,100,000,000 aggregate principal amount of 3.628% Senior Notes due 2035 (collectively, the “Notes”) to be issued by Thermo Fisher International. The Notes will be fully and unconditionally guaranteed by Thermo Fisher.

Item 1.

Description of Registrant’s Securities to be Registered.

The descriptions under the heading “Description of the Notes” in the Prospectus Supplement and “Description of Thermo Fisher International Debt Securities” in the Base Prospectus are incorporated by reference herein.  Copies of such descriptions will be filed with The New York Stock Exchange.

Item 2.

Exhibits.

SIGNATURE

Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934 the Registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereto duly authorized.

	THERMO FISHER SCIENTIFIC INC.
Date:  December 1, 2025	By:	/s/ Thomas B. Shropshire
		Name: Thomas B. Shropshire
		Title: Senior Vice President and General Counsel

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