The 2020–21 season marked Rayo Vallecano's 96th year as a club and their second consecutive campaign in Spain's Segunda División. Spanning from 21 July 2020 to 30 June 2021, the club competed in both the domestic league and the Copa del Rey. The league fixtures were officially announced on 31 August 2020, setting the stage for their promotion push. The season included a promotion play-off section, indicating the team finished in a qualifying position to fight for a spot in La Liga. The squad featured a first-team, a reserve team, and players out on loan, with statistics last updated on 8 March 2021. This campaign was a crucial step in their attempt to return to the top flight of Spanish football.