The Diocese of Gallese (Latin: Dioecesis Gallesina) was a Roman Catholic diocese located in the town of Gallese near the city of Viterbo in the Province of Viterbo. In 1805, it was united with the Diocese of Civita Castellana e Orte to form the Diocese of Civita Castellana, Orte e Gallese. It was restored as a Titular Episcopal See in 1991.