The 2020 United States Senate special election in Arizona was held on November 3, 2020, following the death in office of incumbent Republican U.S. Senator John McCain on August 25, 2018. Governor Doug Ducey was required by Arizona law to appoint a Republican to fill the vacant seat until a special election winner could be sworn in. On September 5, 2018, Ducey appointed former U.S. Senator Jon Kyl to fill McCain's seat. However, Kyl announced he would resign on December 31, 2018.

The 2016 United States Senate election in Arizona was held on November 8, 2016, to elect a member of the U.S. Senate to represent the State of Arizona, concurrently with the 2016 U.S. presidential election, other elections to the U.S. Senate in other states and elections to the U.S. House of Representatives, as well as various state and local elections.