Chris Pappas (D) defeated John Sununu (R) and Edmond Laplante (Constitution Party) to win the general election for U.S. Senate in New Hampshire on November 3, 2026. Incumbent Sen. Jeanne Shaheen (D), who first assumed office in 2009, did not seek re-election.

This U.S. Senate race was among several that helped determine which party controlled the chamber. Heading into the election, Republicans held a 53-45 majority. Democratic presidential candidates won New Hampshire in each election from 2004 to 2024. At the time of the election, New Hampshire had been a Republican trifecta since 2020, meaning Republicans controlled the governorship and both legislative chambers. At the time of the election, New Hampshire's most recent Republican senator was Kelly Ayotte (R), who served in the U.S. Senate from 2011 to 2017 and was the governor at the time of the 2026 election.

The Washington Post's Ben Binday wrote, "In many years, Sununu’s advantages might be enough to win in a state known for political independence and electing politicians from both parties. Yet interviews with dozens of voters ... found an electorate where Trump is so unpopular ... that voters appeared more inclined to cast their ballots based on the Senate candidates’ party affiliations in an election they view as a referendum on Trump’s presidency." According to the Associated Press, "Steve Marchand, a Democratic consultant and former New Hampshire gubernatorial candidate, said Sununu has benefited from national money that got redirected from other states that are no longer seen as top targets, while Democrats were slower to invest."

As of November 2, 2026, Sabato's Crystal Ball and DDHQ/The Hill rated the election Likely Democratic. The Cook Political Report rated it Lean Democratic and Inside Elections rated it Tilt Democratic.

Pappas had represented New Hampshire's 1st Congressional District since 2019. He also served on District 4 of the New Hampshire Executive Council from 2013 to 2019, as treasurer of Hillsborough County from 2007 to 2011, and as a representative of Hillsborough County in the New Hampshire House of Representatives from 2002 to 2006. Pappas' campaign website said, "Chris stood up to Democratic leadership when he called for a ban on stock trading by members of Congress and forced a vote on the House floor. He took on Big Pharma to lower drug prices and cap the cost of insulin at $35. He is taking on corporate polluters who are contaminating our drinking water and is standing up to predatory companies taking advantage of our veterans."

Sununu represented New Hampshire in the U.S. Senate from 2003 to 2009. He also represented New Hampshire's 1st Congressional District from 1997 to 2003. Sununu's father, John H. Sununu (R), and brother, Chris Sununu (R), served as governors of New Hampshire. Sununu's campaign website said, "He’ll oppose all middle-class tax hikes and work to make life more affordable for New Hampshire families by focusing like a laser on reducing inflation and lowering the cost of housing, healthcare, and energy. ... [He’ll] push term limits, make Congress pay for the full cost of their healthcare, and cut Congress’ pay if they vote to shut down the government."

The outcome of this race affected the partisan balance of the U.S. Senate in the 120th Congress. Thirty-three of the 100 U.S. Senate seats were up for election, and another two seats were up for special election. Democrats held 13 of the seats up for election, and Republicans held 22.

At the time of the election, Republicans had a 53-45 majority in the chamber.

This was one of 11 open U.S. Senate races in 2026 in which an incumbent was not running for re-election. Across the country, four Democrats and seven Republicans were not running for re-election — more than any year since 2012. In 2024, eight incumbents — four Democrats, two Republicans, and two independents — did not seek re-election.