The 2021 Ulster Senior Club Football Championship was the 53rd instalment of the annual competition organised by Ulster GAA.

It is one of the four provincial competitions of the 2021–22 All-Ireland Senior Club Football Championship.

The Ulster club championship returned this year after not being held in 2020 due to the COVID-19 pandemic.

[1][2] Kilcoo from Down were the reigning Ulster champions following their victory in the 2019 final over Donegal's Naomh Conaill.

[3] Kilcoo claimed their second Ulster title after a comfortable win against Fermanagh's Derrygonnelly Harps, who were appearing in their first Ulster final.