The Diocese of Liège is a Latin Church ecclesiastical territory or diocese of the Catholic Church in Belgium. The diocese was erected in the 4th century and presently covers the same territory as Belgium's Liège Province, but it was historically much larger. Currently, the diocese is a suffragan in the ecclesiastical province of the Archdiocese of Mechelen-Brussels. Its cathedra is found within St. Paul's Cathedral in the episcopal see of Liège.

The Catholic Church in Belgium, part of the global Catholic Church in Belgium, is under the spiritual leadership of the Pope, the curia in Rome and the Episcopal Conference of Bishops.