The 2020 Wisconsin State Senate elections were taking place as part of the biennial 2020 United States elections. Wisconsin voters elected state senators in 16 of the state's 33 senate districts. State senators serve four-year terms in the Wisconsin State Senate, with roughly half of the seats up for election every two years. The primary elections on August 11, 2020, determined which candidates will appear on the November 3, 2020, general election ballot.