The club competed in the Championship for the fifth consecutive season and finished ninth.

Millwall had a chance of making the play-offs right down the last game day, but ultimately missed out by six points.

Note: Flags indicate national team as has been defined under FIFA eligibility rules.

As part of their pre-season preparations, Millwall announced friendly matches against Gillingham[41] and Ipswich Town.

Source: [citation needed] Millwall's fixtures were announced on 24 June 2021.