2016 United States Senate election in New Hampshire

The 2016 United States Senate election in New Hampshire was held November 8, 2016, to elect a member of the United States Senate to represent the State of New Hampshire, concurrently with the 2016 U.S. presidential election, as well as other elections to the United States Senate in other states, elections to the United States House of Representatives, and various state and local elections. The primary election to select the candidates who appeared on the general election ballot took place on September 13, 2016.

Incumbent Republican Senator Kelly Ayotte ran for re-election to a second term in office and won the primary by a wide margin. Governor Maggie Hassan chose not to seek reelection to a third term as governor and instead sought the nomination of the Democratic Party for the Senate. Hassan was unopposed in the Democratic primary and won the general election by 1,017 votes, representing a winning margin of approximately 0.14%. This made the election the closest race of the 2016 Senate election cycle, and also the closest race in a New Hampshire Senate election since the disputed 1974–75 election. Hassan became the first Democratic senator elected in this seat since the latter election and only the second since 1932.

The Democratic Party also flipped New Hampshire's 1st congressional district in the concurrent House election, thus marking the first time since 1854 that New Hampshire had had an entirely Democratic congressional delegation. To date, this remains the last time that a Democratic candidate for Senate in New Hampshire has failed to win a majority of the vote or lost any county other than Belknap and Coös. This was the first time since 1932 that a Democrat had won a full term to this Senate seat.

This is the last time a senator from New Hampshire lost re-election, and was Ayotte's only election loss of her political career. She was later elected governor of New Hampshire in 2024.