The Diocese of Vieste (Latin: Dioecesis Vestanus) was a Roman Catholic diocese located in the town in the province of Foggia, in the Apulia region of southeast Italy. On 27 June 1818, the diocese of Viesti was granted to the archbishops of Siponto (Manfredonia) as perpetual Administrators. On 30 September 1986, the diocese of Viesti was suppressed, its territory incorporated into the archdiocese of Siponto, and renamed the Archdiocese of Manfredonia–Vieste. Its former cathedral, named in honor of the Assumption of the body of the Virgin Mary into heaven, is now the Vieste Co-cathedral and, like nearly all cathedrals in Italy, a minor basilica.
