Irish Chess Union

The Irish Chess Union (ICU; Irish: Aontas Fichille na hÉireann), is the governing body for chess in Ireland since its formation in 1912. ICU is a member of FIDE since 1933 and the European Chess Union. The ICU promotes chess in Ireland and maintains the chess rating for players registered with the ICU, which are published monthly. It runs competitions such as the Irish Chess Championship and selects teams to participate in international competitions for Ireland.

In 2005, in a dispute over fees, the Ulster Chess Union (UCU), which administers and develops chess in Northern Ireland, decided to end its affiliation with the Irish Chess Union, although the UCU accepted the ICU's continued organisation of the All-Ireland Championships. The UCU's application to affiliate to FIDE was rebuffed. In September 2018 the UCU re-affiliated to the ICU.

Chess in Ireland has been concentrated around the major cities of Dublin, Belfast and Cork; there are also a number of clubs throughout the country such as those in Ballinasloe, Derry, Drogheda, Drumlish, Ennis, Enniscorthy, Galway, Kilkenny, Portadown Lisburn and Wicklow. Leagues are held in the provinces, with the winning teams (and runners-up) playing off in the National Club Championships (although in recent years the Ulster leagues have not participated). The winning team and runners-up are entered into the European Club Championships.