The 2020 United States Senate election in Louisiana was held on November 3, 2020, to elect a member of the United States Senate to represent the State of Louisiana, 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. A blanket primary was held on November 3, 2020; if no candidate had won a majority of the vote in the blanket primary, then a runoff election would have been held on December 5.

William Morgan Cassidy is an American physician and politician serving as the senior United States senator from Louisiana, a seat he has held since 2015. A member of the Republican Party, he served in the Louisiana State Senate from 2006 to 2009 and in the U.S. House of Representatives from 2009 to 2015.