United States Senate elections, 2018 (A World Without Bridgegate)

The 2018 United States Senate elections were held on November 6, 2018. 33 of the 100 seats were contested in regular elections while two others were contested in special elections due to Senate vacancies in Minnesota and Mississippi. The winners were elected to six-year terms running from January 3, 2019, to January 3, 2025. Senate Democrats had 26 seats up for election (including the seats of two independents who caucus with them) while Senate Republicans had nine seats up for election.

To maintain their working majority of 50 Senators and Republican Vice President Susana Martinez (who can cast a tie-breaking vote), Republicans could afford a net loss of four Senate seat in the 2018 elections. The Republicans had a 53-47 majority after the 2016 Senate elections. Two Republican-held seats were open as a result of retirements in Tennessee and Utah, while every Democratic incumbent ran for re-election. Democrats faced what was considered an extremely unfavorable map as they were defending 13 seats in states won by Chris Christie in the 2016 presidential election and 26 in total while Republicans weren't defending any seats in a state won by Hillary Clinton in 2016 and nine in total. Additionally, Democrats were defending five seats in states that Christie won by double digits in 2016.

The Republicans maintained a Senate majority following the 2018 elections defeating six Democratic incumbents in Florida, Missouri, Michigan, Ohio, Pennsylvania, and New Jersey. Democrats won three Republican-held seats, defeating incumbent Jeff Flake in Arizona, Phil Bredesen defeating Marsha Blackburn for retiring Republican Bob Corker's open seat, and winning an open seat in Mississippi after Democrat Mike Espy defeated embattled, controversial Republican candidate Cindy Hyde-Smith.