The 2020–21 season was the 90th season in the existence of CA Osasuna and the club's second consecutive season in the top flight of Spanish football. In addition to the domestic league, Osasuna participated in this season's edition of the Copa del Rey. The season covered the period from 20 July 2020 to 30 June 2021, with the late start to the season due to the COVID-19 pandemic in Spain.