The 2021 St. Louis mayoral election occurred in two stages, with an approval voting 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 narrowly defeated Spencer in the general election, becoming the first African-American woman elected to the office of mayor.