This is a comprehensive list of Catholic dioceses in the island of Ireland. Catholicism in Ireland only maintains a Latin Church hierarchy, encompassing both the Republic of Ireland and Northern Ireland, having been unaffected by the partition of Ireland in 1920–22. There are no Eastern Catholic jurisdictions, nor other exempt ordinariates.
There are 26 dioceses in Ireland, each led by a diocesan bishop (including four Metropolitan Archdioceses). They are organised into a single all-island Episcopal Conference that is based in the primatial see of Armagh. The Holy See is represented by the Apostolic Nuncio to Ireland. A separate Apostolic Nunciature in London represents the Holy See in England, Wales and Scotland.