The 2018 United States Senate election in Delaware took place on November 6, 2018, to elect a member of the United States Senate to represent the State of Delaware, concurrently with other elections to the United States Senate, elections to the United States House of Representatives, and various state and local elections.

Thomas Richard Carper is an American politician and former military officer serving as the senior United States senator from Delaware, having held the seat since 2001. A member of the Democratic Party, Carper served in the United States House of Representatives from 1983 to 1993 and was the 71st governor of Delaware from 1993 to 2001.