The 2021 Leinster Senior Football Championship is the 2021 iteration of the Leinster Senior Football Championship organised by Leinster GAA.
The Leinster championship was contested by 11 of the 12 county teams in Leinster, a province of Ireland. Kilkenny was the only county team not to compete.
The draw for the preliminary rounds and quarter-finals took place on 20 April 2021. The draw for the semi-finals took place on 4 July 2021, after the completion of the quarter-final ties.
Dublin advanced to the 2021 All-Ireland SFC semi-finals.