Elections to the South Dakota Senate were held on November 3, 2020 as a part of the biennial elections in the U.S. state of South Dakota. Voters in 35 single-member constituencies elected members to the 93rd Senate. Elections were also held in the state for U.S. president, the U.S. Senate, the U.S. House, and the South Dakota House of Representatives.
Primary elections were held on June 2, 2020.
The Republican Party had been in majority control of the Senate since 1995, and had not come close to losing it since then. Although the Democratic Party held some support from urban areas and districts with a large Native American population, they had been losing seats over time; the last time Democrats held a number of seats in the double digits was 2010.
Districts where the margin of victory was under 10%:
<span style="color:red;">Red</span> denotes races won by Republicans. <span style="color:blue;">Blue</span> denotes races won by Democrats.