The Diocese of Como is a Latin Church ecclesiastical jurisdiction or diocese of the Catholic Church in northern Italy. It was established in the Fourth Century. It is a suffragan diocese in the ecclesiastical province of the metropolitan Archdiocese of Milan. The Bishop of Como's cathedra is in the Como Cathedral.

The Archdiocese of Milan is a Latin Church ecclesiastical territory or archdiocese of the Catholic Church in Italy which covers the areas of Milan, Monza, Lecco and Varese. It has long maintained its own Latin liturgical rite usage, the Ambrosian rite, which is still used in the greater part of the diocesan territory. Among its past archbishops, the better known are Ambrose, Charles Borromeo, Pope Pius XI and Pope Paul VI.