The 1990–91 Irish League Cup (known as the Roadferry Freight League Cup for sponsorship reasons) was the 5th edition of the Irish League Cup, Northern Ireland's secondary football knockout cup competition.
Glenavon unsuccessfully defended its 1990 title in the second round losing to Larne.
Lane would unsuccessfully defend its pursuit of the cup in the quarter final losing to Ards.
Glentoran successfully defended its pursuit of the cup defeating Ards in the final, 2-0.
Glentoran would become the first to earn successive titles.