The Roman Catholic Diocese of Valdivia (Latin: Valdivien(sis)) is a Latin Rite suffragan diocese in the ecclesiastical province of Concepción in Chile.

Its cathedral episcopal see is Catedral Nuestra Señora del Rosario, dedicated to Our Lady of the Rosary, in the city of Valdivia, Los Ríos.

As per 2014, it pastorally served 145,500 Catholics (47.2% of 308,000 total) on 13,679 km² in 17 parishes with 27 priests (10 diocesan, 17 religious), 28 deacons, 60 lay religious (18 brothers, 42 sisters) and 2 seminarians (all Roman rite)