The 2021 Big South men's basketball tournament was the postseason men's basketball tournament that ended the 2020–21 NCAA Division I men's basketball season of the Big South Conference.
It was held from February 27 through March 7, 2021 and all tournament games were played on home arenas of the higher-seeded school.
All of the conference teams, except for Charleston Southern, competed in the tournament.
Charleston Southern cancelled their season after going 3–18 due to contact tracing, so they did not compete in the conference tournament.
Teams were seeded by record within the conference, with a tiebreaker system to seed teams with identical conference records.