The following is a list of the Catholic dioceses in Italy. As of May 2017, the Catholic Church in Italy is divided into sixteen ecclesiastical regions. While they are similar to the 20 civil regions of the Italian state, there are some differences. Most ecclesiastical regions are in turn divided into a number of ecclesiastical provinces. The provinces are in turn divided into a number of dioceses. The sovereign state of Vatican City is part of the metropolitan province of Rome. A metropolitan bishop exercises a degree of leadership over a group of dioceses that are loosely subject (suffragan) to the care of the metropolitan see. This list excludes those archdioceses, dioceses and ecclesiastical territories that are immediately subject to the Holy See.
There are 227 sees ('particular churches'), most of which are dioceses led by a bishop. A diocese that is led by an archbishop is known as an archdiocese. There are 40 Metropolitan archdioceses which serve as the seat of an ecclesiastical province. This number includes the Holy See and the Patriarchate of Venice. There are also four archdioceses which are non-metropolitan, having been demoted by papal decree. This brings the number of archbishops in Italy and Vatican City to 44 (i.e. 40 + 4).