It started on 19 September 2020 with the first round of the regular season and ended on 15 June 2021 with the finals.

TD Systems Baskonia was the defending champion which got knocked out by Valencia Basket in the quarterfinals.

Barça swept the series and completed its first Spanish double (League and Cup titles) since 2011.

A total of 19 teams contested the league, including the same 18 sides from the 2019–20 season and one promoted from the 2019–20 LEB Oro.

On May 17, 2021, the Ministry of Culture of Spain, the Ministry of Health of Spain and the Spanish High Council for Sports allowed the return of the spectators to the league arenas for the last two regular season rounds and for the playoffs with the following requirements:[45][46] On June 2, 2021, the Spanish High Council for Sports allowed the general admission of the spectators for the playoffs, indicating that the maximum number of spectators is 1,000 people.