Leinster Under-20 Football Championship

The Leinster GAA Football Under-20 Championship, known simply as the Leinster Under-20 Championship, is an annual inter-county Gaelic football competition organised by the Leinster Council of the Gaelic Athletic Association (GAA). It is the highest inter-county football competition for male players between the ages of 17 and 20 in the province of Leinster. The championship was contested as the Leinster Under-21 Championship between 1964 and 2016 before changing to an under-20 age category from 2018. It is sponsored by EirGrid.

The final, currently held in July, serves as the culmination of a series of games played during a five to six-week period, and the results determine which team receives the Flood Cup. The championship has usually been played on a straight knockout basis whereby once a team loses they are eliminated from the championship.

The Leinster Championship is an integral part of the wider GAA Football Under-20 All-Ireland Championship. The winners of the Leinster final, like their counterparts in the other three provinces, advance to the semi-final stage of the All-Ireland series of games.

Eleven teams currently participate in the Leinster Championship, with Kilkenny remaining the only county not to field a team. The title has been won at least once by eight teams, with seven of these winning the title more than once.