The 2021 St. Louis mayoral election occurred in two stages, with a unified primary on March 2, 2021, and a two-candidate general election on April 6, 2021. Incumbent Democratic mayor Lyda Krewson was eligible to seek re-election to a second term in office, but chose to retire. In a primary field of four candidates, St. Louis Treasurer Tishaura Jones and Alderwoman Cara Spencer advanced to the general election. Jones defeated Spencer in the general election by nearly 4% of votes cast, becoming the first African-American woman elected to the office of mayor.