Sau Reservoir (; ) is a reservoir located on the Ter river, near Vilanova de Sau, Catalonia, Spain. The dam was completed in 1962, creating a reservoir with a storage capacity of 151.3 hmó that covered the former town of Sant Romàde Sau. The Church of Sant Romàis still visible when the water level is low. The dam has a structural height of 83 m and a crest length of 260 m.