The 2020–21 season was RKC Waalwijk's second consecutive season in the top flight of Dutch football, the Eredivisie.

In addition to the domestic league, RKC Waalwijk participated in the KNVB Cup.

The season covered the period from 1 July 2020 to 30 June 2021.

Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.

Players may hold more than one non-FIFA nationality.