The Diocese of Kildare and Leighlin (; ; ) is a Latin Church diocese of the Catholic Church in eastern Ireland. It is one of three suffragan dioceses in the ecclesiastical province of Dublin and is subject to the Archdiocese of Dublin. On 7 May 2013, Denis Nulty was appointed bishop of the diocese.
The united diocese includes virtually all of County Carlow, most of County Kildare and parts of counties Offaly, Laois, Kilkenny, Wexford and Wicklow. The largest towns in the diocese are Carlow, Edenderry, Kildare, Naas, Newbridge, Portarlington and Portlaoise.
These two dioceses continued to be separate from their foundation until 1678, when, owing to the extreme tenuity of the episcopal revenues, the bishopric of Leighlin was given in commendam by the Holy See to the Bishop of Kildare. The Cathedral Church of the Assumption of the Blessed Virgin Mary is located in the town of Carlow.
Today, with the help of enthusiastic lay people, the diocese is actively engaged in nurturing the faith of local youth. A key example of this is its involvement in the John Paul II Awards. The award was launched by the Papal Nuncio to Ireland, Giuseppe Lazzarotto on 7 November 2006 in the Diocese of Derry, Northern Ireland. It is dedicated to Pope John Paul II due to the strong beliefs and confidence he had in the youth of the world today.
The united Diocese of Kildare and Leighlin is divided into seven deaneries, each divided into a number of parishes or group parishes.
The following is a basic list of the Bishops of Kildare and Leighlin.