Roman Catholic Diocese of Viana do Castelo

The Diocese of Viana do Castelo (Dioecesis Vianensis Castelli), is a Latin Church diocese of the Catholic Church in the Norte Region of Portugal. It has existed since 1977. It is a suffragan of the archdiocese of Braga, with its see at Viana do Castelo.

The current bishop is João Evangelista Pimentel Lavrador.