The 2021 Atlanta United FC season was the fifth season of Atlanta United FC's existence, and the thirteenth year that a professional soccer club from Atlanta, Georgia competing in the top division of American soccer. Atlanta United played their home games at Mercedes-Benz Stadium. Outside of MLS, they will participate in the 2021 U.S. Open Cup as defending champions, as the previous year's tournament was canceled due to the COVID-19 pandemic. Due to the cancelation of the 2020 edition however, Atlanta United will compete in the 2021 CONCACAF Champions League as the final berth was given to the defending champions of the U.S. Open Cup.