St Magnus Church, St Magnus' Church or St Magnus's Church may refer to one of several churches dedicated to a St Magnus:
Magnus of Anagni Santi Michele e Magno, Rome Magnus of Füssen St. Mang's Abbey, Füssen Magnuskirche, Worms Magnus the Martyr St Magnus-the-Martyr, London St Magnus Cathedral, Kirkwall, Orkney St Magnus Church, Egilsay, Orkney Orphir Roundchurch, Orphir, Orkney Magnus Cathedral, Faroe Islands