This is a list of qualifying teams for the 2021 NCAA Division I men's basketball tournament. A total of 68 teams participated in the tournament. 31 of the teams earned automatic bids by winning their conference tournaments; normally, this would be 32 teams, but the Ivy League cancelled play for this season. The remaining 37 (normally 36) teams were granted at-large bids, which were extended by the NCAA Selection Committee. All teams were seeded 1 to 16 within their regions, while the Selection Committee seeded the entire field from 1 to 68.[1][2]
In contrast to previous years, the S-Curve used to establish overall seeds will also be used as primary determinant of the tournament bracket; this was made possible by the relatively condensed locations of this year's tournament making geographic concerns irrelevant. However, rules that can modify pairings to avoid early rematches and to distribute top conference representatives to different regions will remain in effect.[3][4]