Executive Change

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): January 12, 2026 THERMO FISHER SCIENTIFIC INC. (Exact name of Registrant as specified in its Charter) Delaware 1-8002 04-2209186 (State or other jurisdiction of incorporation) (Commission File Number) (I.R.S. Employer Identification No.) 168 Third Avenue Waltham , Massachusetts 02451 (Address of principal executive offices) (Zip Code) Registrant’s telephone number, including area code: ( 781 ) 622-1000 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): ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Title of each class   Trading Symbol(s)   Name of each exchange on which registered Common Stock, $1.00 par value   TMO   New York Stock Exchange 3.200% Notes due 2026     TMO 26B   New York Stock Exchange 1.400% Notes due 2026     TMO 26A   New York Stock Exchange 1.450% Notes due 2027   TMO 27   New York Stock Exchange 1.750% Notes due 2027   TMO 27B   New York Stock Exchange Floating Rate Senior Notes due 2027   TMO 27D   New York Stock Exchange 0.500% Notes due 2028   TMO 28A   New York Stock Exchange 1.375% Notes due 2028   TMO 28   New York Stock Exchange 1.950% Notes due 2029   TMO 29   New York Stock Exchange 0.875% Notes due 2031   TMO 31   New York Stock Exchange 2.375% Notes due 2032   TMO 32   New York Stock Exchange 3.650% Notes due 2034   TMO 34   New York Stock Exchange 3.628% Senior Notes due 2035   TMO 35A   New York Stock Exchange 2.875% Notes due 2037   TMO 37   New York Stock Exchange 1.500% Notes due 2039   TMO 39   New York Stock Exchange 1.875% Notes due 2049   TMO 49   New York Stock Exchange Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐ Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. Each of Michel Lagarde and Frederick M. Lowery have notified Thermo Fisher Scientific Inc. (the “Company”) of their decisions to leave the Company to pursue other opportunities. Mr. Lagarde, who has served as Executive Vice President and Chief Operating Officer of the Company since 2021 will depart on March 31, 2026, and Mr. Lowery, who has served as an Executive Vice President of the Company since 2024 will depart on February 28, 2026. Effective March 1, 2026, Thermo Fisher Scientific will update its organizational structure and leadership team. Marc N. Casper will become Chairman and Chief Executive Officer. Gianluca Pettiti, currently an Executive Vice President, will be promoted and transition to the role of President and Chief Operating Officer. Also, as of that date, Michael Shafer, currently an Executive Vice President, will be promoted to an expanded role and will report directly to the Chief Executive Officer. 2 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 hereunto duly authorized.   THERMO FISHER SCIENTIFIC INC.         Date:   January 12, 2026 By: / s / Thomas B. Shropshire       Thomas B. Shropshire       Senior Vice President and General Counsel 3