The 1999–2000 Irish Cup was the 120th edition of the Irish Cup, Northern Ireland's premier football knock-out cup competition. It concluded on 6 May 2000 with the final.

Portadown were the defending champions, winning their 2nd Irish Cup last season after Cliftonville were disqualified from the 1999 final. This season Portadown reached the final again, but were defeated 1–0 by Glentoran, who won the cup for the 18th time.

Results Preliminary round

Replays

First round

Replays

Second round

Replay

Third round

Fourth round

Replays

Fourth round (A)

Fifth round

Replay

Sixth round

Replays

Quarter-finals

Replay

Semi-finals

Replay

Final

References