The 2021 Dublin Senior Football Championship was the 135th edition of Dublin GAA's premier gaelic football tournament for senior clubs in County Dublin, Ireland. 32 teams participate (16 in Senior 1 and 16 in Senior 2), with the winner of Senior 1 representing Dublin in the Leinster Senior Club Football Championship. Kilmacud Crokes defeated St Jude's to win the Senior 1 Championship. St Pat's Donabate won the 2021 I.F.C. and were promoted along with I.F.C. finalists Round Towers Clondalkin to Senior 2. They replaced St Peregrines and Fingal Ravens who were relegated to the 2022 I.F.C.