The 1977–78 Irish Cup was the 98th edition of the Irish Cup, Northern Ireland's premier football knock-out cup competition. It began on 4 February 1978, and concluded on 29 April 1978 with the final.
The defending champions were Coleraine, after they defeated Linfield 4–1 in the 1976–77 final.[1] However, Linfield gained revenge by knocking the holders out with a 2–1 win in the first round. Linfield went on to win the cup for the 31st time, defeating Ballymena United 3–1 in the final.[2]