The 2021 FFA Cup preliminary rounds were the qualifying competition to decide 23 of the 32 teams to take part in the 2021 FFA Cup.
The competition commenced in February and was completed in November.
[1] There were changes to the make-up of the entrants compared to the 2019 edition, with South Australia's qualifying places increasing from 1 to 2, and NSW losing one place.
[2] Additionally, the top eight placed A-League clubs for the 2020–21 A-League season gained automatic qualification to the Round of 32.
[3] The preliminary rounds structures were as follows, and refer to the different levels in the unofficial Australian association football league system: The draw for the qualifying round was conducted on 4 February 2021.