Christ Church Cathedral, more formally The Cathedral of the Holy Trinity, is the cathedral of the United Dioceses of Dublin and Glendalough and the cathedral of the ecclesiastical province of the United Provinces of Dublin and Cashel in the (Anglican) Church of Ireland. It is situated in Dublin, Ireland, and is the elder of the capital city's two medieval cathedrals, the other being St Patrick's Cathedral.

The United Dioceses of Dublin and Glendalough is a diocese of the Church of Ireland in the east of Ireland. It is headed by the Archbishop of Dublin, who is also styled the Primate of Ireland. The diocesan cathedral is Christ Church Cathedral, Dublin.