The 2003–04 Irish Cup was the 124th edition of the Irish Cup, Northern Ireland's premier football knock-out cup competition.

[1] Coleraine were the defending champions, winning their 5th Irish Cup last season after a 1–0 win over Glentoran in the 2003 final.

This season the same two clubs reached the final again.

A 1–0 victory for Glentoran, who were appearing in the final for the sixth time in nine years was enough to seal their 20th Irish Cup win.

[2][3] The following teams were given byes into the second round: Strabane, Kilbride Swifts, Newington, Ballymacash Rangers, Richhill, Queen's University, and Killymoon Rangers.