The Diocese of Guardialfiera or Diocese of Guardia was a Roman Catholic diocese in Italy. The diocese was established in the second half of the 11th century, with seat of the diocese was located in the city of Guardialfiera in the Province of Campobasso in the region of Molise. In 1818, the diocese was suppressed, and its ecclesiastical territory was assigned to the Diocese of Termoli.

The Diocese of Termoli-Larino is a Latin Church diocese of the Catholic Church situated in the province of Campobasso, region of Molise. The commune of Termoli is an important regional seaport. The diocese has existed in its current configuration since 1986, when the diocese of Larino was suppressed and added to its territory. It is a suffragan of the archdiocese of Campobasso-Boiano.