The 2017–18 Irish Cup (known as the Tennent's Irish Cup for sponsorship purposes) was the 138th edition of the premier knock-out cup competition in Northern Irish football since its introduction in 1881. The competition began on 19 August 2017 and concluded with the final at Windsor Park in May 2018. Linfield are the defending champions, having defeated Coleraine 3–0 in the 2017 final.