Incumbent Al Green (D), Gretchen Brown (D), Amanda Edwards (D), and Christian Menefee (D) are running in the Democratic primary for Texas' 18th Congressional District on March 3, 2026. As of January 2026, Green, Edwards, and Menefee led in local media attention.

The primary is taking place in the context of redistricting in Texas ahead of the 2026 elections. Green was elected to represent the 9th District in 2024 and is running for re-election in the 18th District after redistricting shifted the 9th District towards Republicans and moved Green's home address into the 18th District. Sylvester Turner (D) was elected to represent the 18th District in 2024. Turner died in March 2025.

Edwards and Menefee were the top two finishers in the special election to replace Turner. The two advanced to a January 31 runoff after neither won an outright majority in the special election. The runoff is taking place under the district lines used for the 2024 election rather than the lines used for the 2026 primary. The winner of the runoff between Edwards and Menefee will be sworn into Congress before the March 3 primary.

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."

Edwards is a municipal finance attorney and former member of the Houston City Council. Edwards says she is running because "we are standing in an unprecedented moment in our nation -- a moment of true generational change...[we] need the next generation of new leaders in Washington to combat President Trump’s attacks on jobs, education, healthcare access."

Menefee is a litigator and was elected the Harris County Attorney in 2020, when he defeated incumbent Vince Ryan (D). 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."

If no candidate wins 50% or more of the vote, the top two finishers will advance to a May 26 runoff. As of January 2026, major election forecasters rated the general election Solid/Safe Democratic.

According to an Inside Elections analysis of Texas' redistricting ahead of the 2026 elections, the 2024 version of the 9th District—where Green was elected—had a partisan baseline of D+48 and the 2024 version of the 18th District had a partisan baseline of D+39. The partisan baseline of the 2026 version of the 18th District is D+61.