The 2003 Ulster Senior Football Championship was the 115th instalment of the annual Ulster Senior Football Championship organised by Ulster GAA. It was one of the four provincial competitions of the 2003 All-Ireland Senior Football Championship.
Tyrone won their 10th title overall and their first title since 2001. Armagh, the defending Ulster and All-Ireland Champions were eliminated by Monaghan in the preliminary round.
Nine counties competed in the Ulster Senior Football Championship:
The draw for the 2001 Championship was made on 12 November 2000.