Saint Petroc (sometimes spelt Petrock in English, Perog in Welsh and Perreux in French) (d. 564) is a 6th century Celtic Christian saint. He was born in Wales but primarily ministered to the Britons of Dumnonia which included the modern counties of Devon (Dewnans), Cornwall (Kernow), and parts of Somerset (Gwlas an Hav) and Dorset. He is also known to have ministered to the people of Brittany.