Incumbent Marie Gluesenkamp Perez (D) and John Braun (R) advanced from the top-two primary in Washington's 3rd Congressional District on August 4, 2026. Perez and Braun defeated seven other candidates. As of July 2026, Perez, Braun, and Brent Hennrich (D) led in fundraising and local media attention.

The Oregonian's Betsy Hammond said Perez "is one of the most centrist Democrats in Congress and has earned the ire of many progressives in her district." The Seattle Times' Danny Westneat said, "Gluesenkamp Perez has a traditional GOP opponent, state Senate Minority Leader John Braun, R-Centralia. But she’s also facing a more-robust-than-expected fusillade from the left, in progressive challenger Brent Hennrich."

Perez was first elected in 2022. Perez's campaign website said she was "ranked as one of the most bipartisan lawmakers in the House and regularly works across the aisle to fix what's broken ... [she was] the kind of working-class Washingtonian left behind in this economy. The political establishment in DC ignored folks like her." The American Israel Public Affairs Committee (AIPAC) endorsed her.

Braun was elected to the Washington Senate in 2012 and had, as of the 2026 election, served as minority leader since 2020. He was a U.S. Navy veteran and manufacturing executive. Braun's campaign website said he "spent 31 years in the submarine force, built a 350-employee company in Chehalis, and led the fight against Olympia's tax surge. Now he's running to bring that same discipline to Washington, D.C." President Donald Trump (R) endorsed him.

Hennrich was a former cinema operations manager with Cinemark and Christie Digital Systems. Hennrich ran to represent the district in 2022 but suspended his campaign and did not appear on the primary ballot. In a speech at the Democratic Party of Washington's state convention, Hennrich said, "I’m running unfortunately against the most MAGA and Trump-aligned Democrat in the entire House." Progressive Victory endorsed him.

Also running in the primary were Austin Braswell (D), Troy Rasband (D), Lawrence Kellogg (R), John Roco (R), Antony Barran (Cascade Party), and John Saulie-Rohman (Independent Party).

In a top-two primary, all candidates running for a particular office appear on the same primary ballot. The top two finishers advance to the general election regardless of their partisan affiliation.

As of July 2026, major election forecasters rated the general election either Toss-up or Lean Democratic. Perez defeated Joe Kent (R) 51.7%–47.9% in 2024 and 50.1%–49.3% in 2022.