The 2020–21 ASUN Conference men's basketball season began with practices in October 2020, followed by the start of the 2020–21 NCAA Division I men's basketball season in November. Conference play began in January 2021 and concluded in March 2021. It was the 43rd season of ASUN Conference basketball. This season was also the first ASUN season for Bellarmine, which started a transition from NCAA Division II when it joined the ASUN on July 1, 2020.