Representative Michael McCaul, the 11-term Texas Republican known for his work in national security and foreign policy, said on Sunday that he would not seek re-election in 2026.

“It’s been an honor to serve over two decades in the Congress,” he said during an interview on “This Week” on ABC, where he made the announcement. “I’m looking now for a new challenge.”

Mr. McCaul has served as chairman of both the House Foreign Affairs and Homeland Security Committees. He is the latest in a string of Republicans who have announced plans to leave the House after next year’s elections, but he is only the third departing Republican to do so without seeking another elected office.

Representatives Don Bacon of Nebraska and Morgan Luttrell of Texas also announced plans this year to retire and step back from public office.

Mr. McCaul’s influence in office extended to a variety of domestic and foreign policy issues, including his support for military aid to Ukraine, his persistent calls for strong policies against China and his outspoken support for security measures at the U.S.-Mexico border.

On Sunday, he said he planned to seek opportunities to continue working in his areas of interest. “I want to continue serving the people of this country in national security and foreign policy and do what I’ve done for the last two decades to make America stronger and the world safer”

Mr. McCaul won re-election in 2024 in his safely Republican district with about 64 percent of the vote. After a rare mid-decade redistricting push by Republican leaders in Texas, the district was redrawn in August to become even more solidly Republican.