The 2020 United States Senate elections were held on November 3, 2020, with the 33 class 2 seats of the Senate contested in regular elections. Of these, 21 were held by Republicans, and 12 by Democrats. The winners were elected to 6-year terms from January 3, 2021, to January 3, 2027. Two special elections for seats held by Republicans were also held in conjunction with the general elections: one in Arizona, to fill the vacancy created by John McCain's death in 2018; and one in Georgia, following Johnny Isakson's resignation in 2019. These elections ran concurrently with the 2020 United States presidential election in which incumbent president Donald Trump lost to Democratic nominee Joe Biden.

The 2020 United States Senate election in Colorado was held on November 3, 2020, to elect a member of the United States Senate to represent the State of Colorado, concurrently with the 2020 U.S. presidential election, as well as other elections to the United States Senate, elections to the United States House of Representatives and various state and local elections.