Littelfuse, Inc.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers On August 6, 2026, the Board of Directors (the “Board”) of Littelfuse, Inc. (the “Corporation”) increased the number of members of the Board from eight to nine and appointed Todd Kelsey to the Board to fill the resulting vacancy, effective August 6, 2026. Mr. Kelsey was also appointed to the Compensation Committee of the Board. Mr. Kelsey will hold office until his successor is duly elected and qualified or upon his earlier death, resignation or removal. There are no arrangements or understandings between Mr. Kelsey and any other person pursuant to which Mr. Kelsey was appointed as a director. The Board has determined that Mr. Kelsey is an independent director under the listing standards of the Nasdaq Stock Market and is independent for the purposes of Rule 10A-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Mr. Kelsey also is not a party to any transactions requiring disclosure pursuant to Item 404(a) of Regulation S-K under the Exchange Act. Mr. Kelsey is the President and Chief Executive Officer of Plexus Corp. Plexus is a $4.5 billion global technology enterprise with 20,000 employees at 27 sites across seven countries - the U.S, Mexico, China, Malaysia, Thailand, Romania, and the U.K. -- generating well over half its revenue internationally. Plexus partners with leading OEMs to help create the products that build a better world, by designing, manufacturing and servicing some of the world's most transformative products in the Aerospace/Defense, Industrial, SemiCap, Data Center, and Healthcare/Life Sciences markets. Mr. Kelsey assumed the role of President and Chief Executive Officer of Plexus in 2016. Prior to that, Mr. Kelsey held the positions of Executive Vice President and Chief Operating Officer, Executive Vice President of Global Customer Services and Senior Vice President of Engineering Solutions, among others, of Plexus. He joined Plexus in 1994 as a Design Engineer in the Engineering Solutions group. Beyond his executive leadership at Plexus, Mr. Kelsey has served on multiple corporate and community boards, including serving as the Vice Chair of the Board and Audit Committee Chair for Steelcase Inc., a global provider of workplace products, furnishings and services. He is currently Vice Chair of the Board for Wisconsin Manufacturers and Commerce. Mr. Kelsey earned a BS and an MS in electrical engineering from the University of Wisconsin-Madison and an MBA from the University of Wisconsin-Oshkosh. As a non-employee director, Mr. Kelsey will receive compensation in accordance with the Corporation’s non-employee director compensation practices, which are described in the Corporation’s definitive proxy statement filed with the Securities and Exchange Commission on March 12, 2026. As part of such compensation, Mr. Kelsey will receive an initial equity award consisting of a pro-rated portion of the annual award of restricted stock units made to independent directors.

Item 7.01 Regulation FD Disclosure. A copy of the press release announcing the appointment of Mr. Kelsey is attached as Exhibit 99.1 and incorporated herein by reference. The exhibit furnished under Item 7.01 of this Current Report shall not be deemed “filed” for purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing by the Company under the Securities Act of 1933 or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.