Sarah Trone Garriott (D) defeated incumbent Zach Nunn (R) in the general election for Iowa's 3rd Congressional District on November 3, 2026.

Iowa Public Radio's Isabella Luu said the 3rd District "hasn’t been held by any incumbent for more than two terms since 2010." Nunn defeated then-incumbent Cindy Axne (D) 50.3%–49.6% in 2022 and won re-election 51.8%–47.9% in 2024. That year, Donald Trump (R) defeated Kamala Harris (D) 51.6%–47.1% in the presidential election in the district. As of November 2026, major election forecasters rated the general election Lean Democratic or Tilt Democratic.

Trone Garriott had represented the 14th District in the Iowa Senate since 2023. She was, as of the 2026 election, a pastor in the Evangelical Lutheran Church of America and an executive at a food bank network. Trone Garriott's campaign website said, "She is the only Democrat in Iowa over the past few years who has consistently won competitive elections in Republican districts, and now she is running for Congress in IA-03 to ensure Iowans have a voice in Washington. Her journey from service worker to minister, nonprofit leader, and state legislator is a testament to her unwavering commitment to public service and the people of Iowa."

Nunn was, as of the 2026 election, a colonel in the U.S. Air Force Reserve and a former cybersecurity consultant and National Security Council staffer. Before his election to the U.S. House in 2022, Nunn served four years each in the Iowa Senate and the Iowa House of Representatives. Nunn's campaign website said, "Zach Nunn knows Iowa’s strength comes from putting our communities first. His public service is a proven record of delivering for Iowans with hard work and innovative solutions. As a combat aviator with the US Air Force, Zach is a fighter for America. Zach will never stop fighting for Iowans’ individual liberties, fiscal discipline, and limited government."

As of November 2, 2026, Nunn had raised $6.12 million and Trone Garriott had raised $8.07 million.

The outcome of this race affected the partisan balance of the U.S. House of Representatives in the 120th Congress. All 435 U.S. House districts were up for election.

At the time of the election, Republicans had a 219-214 majority with two vacancies in the U.S. House.