Incumbent Reps. Al Green (D) and Christian Menefee (D) are running in the Democratic primary runoff for Texas' 18th Congressional District on May 26, 2026. Menefee and Green were the top two finishers in the March 3 primary with 46.0% and 44.2% of the vote, respectively. They advanced because neither received more than 50% of the vote.

The primary is taking place in the context of redistricting in Texas ahead of the 2026 elections. In 2024, Green won election in the 9th District. Redistricting in 2025 made the 9th more Republican, and also shifted Green's home to the new 18th District. Sylvester Turner (D) was elected to represent the 18th District in 2024. Turner died in March 2025. Menefee won the January 31 special runoff election for the remainder of Turner's term.

The special election took place in the 2024 version of the 18th District. The Texas Tribune's Gabby Birenbaum said the new 18th District "contains far more voters from Green’s old district than Menefee’s. But Menefee has been running for office for nearly a year and had a robust campaign operation that pivoted quickly to the primary in the new district after the November special election and January runoff in his current district."

As of March 2026, this race is projected to be one of two incumbent-versus-incumbent U.S. House elections in 2026. The Hill's Julia Mueller and Caroline Vakil said, "age and generational change has become a focal point in the race, particularly in Texas, where two senior Democrats — Turner and Rep. Sheila Jackson Lee — died in the last few years."

Green was first elected to the House in 2004. Green worked as an attorney in private practice and served as president of the Houston branch of the NAACP. Green is running on his record: "You know that I will stand up to Donald Trump because you saw me do it...You know that I will fight for your health care because you’ve seen me do it. You know that I believe in raising the minimum wage to $25 an hour, because you’ve heard me say it."

Menefee was elected to represent the 18th District in a January 31 special election and previously served as Harris County Attorney. Menefee says he is running "because working people deserve a government that has their back...Christian has spent his career fighting back against bullies, and he’s ready to do it in Washington."

As of March 2026, major election forecasters rated the general election Solid/Safe Democratic.