Bầu cử Thượng viện Hoa Kỳ tại Arizona năm 2018

The 2018 United States Senate election in Arizona took place on November 6, 2018. Incumbent Republican Senator Jeff Flake did not seek a second term. The election was held concurrently with a gubernatorial election, other elections to the U.S. Senate, elections to the U.S. House of Representatives, and various other state and local elections.

Primaries were held on August 28, 2018, three days after the death of longtime U.S. Senator John McCain. Martha McSally won the Republican nomination, while Kyrsten Sinema won the Democratic nomination. Green Party candidate Angela Green was also on the ballot, but ended her campaign and endorsed Sinema before Election Day.

The Associated Press called the race for Sinema on November 12, 2018, and McSally conceded that day. Sinema became the first Democrat to win a U.S. Senate seat in Arizona since 1988. McSally was subsequently appointed by Governor Doug Ducey to the other vacant Senate seat in Arizona, left open after McCain's death and then held on an interim basis by Jon Kyl.