Incumbent Tony Gonzales (R) and Brandon Herrera (R) were the top two finishers among four candidates running in the Republican primary for Texas' 23rd Congressional District on March 3, 2026. Because no candidate won more than 50% of the vote, Gonzales and Herrera advanced to a runoff on May 26, 2026. Gonzales and Herrera led in fundraising and local media attention.

This was a rematch of the 2024 primary. Gonzales defeated Herrera 50.6%–49.4% in the runoff after neither candidate won a majority in that year's primary. The Texas Tribune's Owen Dahlkamp described the 2026 primary as "yet another proxy war between the more centrist Gonzales and the right-wing, fire-breather Herrera."

Gonzales was first elected to the House in 2020. The Texas Tribune's Renzo Downey described Gonzales as "a centrist from San Antonio and U.S. Navy veteran." Gonzales highlighted the following accomplishments and said he had delivered for the district during his three terms in office: securing funding to hire more than 100 police officers in the district, opening a South Texas facility for treating the screwworm livestock parasite, and appropriating more than $4.7 billion in funding for healthcare for veterans. President Donald Trump (R) endorsed Gonzales in 2026 after not endorsing him in either 2024 or 2022.

Herrera described himself as "an entrepreneur, Second Amendment activist, and social media personality" who, as of the election, owned a firearms manufacturing company (The AK Guy) and operated a firearms-related YouTube channel. In his 2026 campaign kickoff, Herrera said, "It started to eat at me. Those things that I didn't like about D.C., about my congressman, they didn't change...as much as it's more comfortable to just look the other way, I can't bow out of a fight if I know I can make a difference. It's just not how I'm wired."