The diocese of Terni-Narni-Amelia (Latin: Dioecesis Interamnensis-Narniensis-Amerina) is a Roman Catholic ecclesiastical territory in Umbria, central Italy. It was created in 1983, when the Diocese of Amelia was united to the Diocese of Terni e Narni. The latter had been in turn created in 1907, when the Diocese of Narni was united to the historical Diocese of Terni.