Incumbent Julie Johnson (D) and Colin Allred (D) advanced to a May 26 runoff after neither candidate received more than 50% of the vote in the Democratic primary for Texas' 33rd Congressional District on March 3, 2026. As of March 2026, Johnson and Allred led in fundraising, endorsements, and local media attention.

Allred was first elected to represent an earlier version of the district in 2018. In 2024, Allred ran for U.S. Senate rather than seeking re-election and Johnson was elected to the U.S. House. Allred ran for U.S. Senate in 2026 before dropping out of that race and re-filing for the 33rd District.

The Texas Tribune's Gabby Birenbaum said the primary "takes on additional novelty given that the two candidates are vying for a new district that includes unfamiliar turf for both," as Texas' redistricting ahead of the 2026 elections changed district lines. Birenbaum said the "new boundaries contain about a third of the residents from the old 32nd District that both Allred and Johnson have represented."

Before her election to Congress, Johnson served six years in the Texas House of Representatives and worked as a litigation attorney in private practice. Johnson said she was running "to fight for the people who are too often overlooked and to make sure North Texans are not an afterthought." In an interview with Lone Star Politics, Johnson said Allred "was soundly rejected by the voters in the last election cycle, and he’s been soundly rejected this cycle. And I think he needs to take some introspection and look at why he couldn’t poll more favorably."

Allred had worked as a professional athlete, civil rights attorney, and staff member at the U.S. Department of Housing and Urban Development under President Barack Obama (D). Allred said he was running "to fight for Texans who work hard and play by the rules but never feel like they can win." Allred said he felt "a responsibility to those folks to try and make sure that we have a unified party going into November, and that I could best serve by looking at serving my hometown and the place where I was born and raised."