The Diocese of Ossero or Diocese of Osor (Latin: Dioecesis Arbensis) was a Roman Catholic diocese located in the port town of Ossero on the island of Cres in Primorje-Gorski Kotar County in western Croatia. In 1828, it was suppressed along with the Diocese of Arbe to the Diocese of Krk.[1][2] In 1933 it was restored as a Titular Episcopal See.[2]