The 1998–99 Irish League Cup (known as the Coca-Cola League Cup for sponsorship reasons) was the 13th edition of Northern Ireland's secondary football knock-out cup competition. It concluded on 4 May 1999 with the final. The competition was re-structured this season, allowing only the 10 top-flight clubs and the 8 second-tier clubs to enter. This reduced the number of clubs taking part from 32 down to 18.