1990 O'Byrne Cup

The 1990 O'Byrne Cup was a Gaelic football competition contested by the county teams of Leinster GAA.

The tournament format was straight knockout, with 11 participating teams. Dublin did not enter the competition. First-round byes were awarded to Laois, Louth, Meath, Longford and Kildare.

Louth won the competition after defeating Kildare in the final, held at the Drogheda Gaelic Grounds.