St. Magnus' Cathedral, Kirkwall dominates the skyline of Kirkwall, the main town of Orkney, a group of islands off the north coast of Scotland. It is Britain's most northerly cathedral, a fine example of Norman architecture built for the Bishops of Orkney when the islands were ruled by the Norse Earls of Orkney.

The Romanesque Cathedral begun in 1137 and is attributed to masons from Durham Cathedral. The masonry uses red sandstone quarried near Kirkwall and yellow sandstone from the island of Eday, often in alternating courses or in a chequerboard pattern to give a polychrome effect.

As completed during the twelfth century, the original Cathedral had three aisled bays to the chancel with the bay at the east end shorter, and apsed in a similar way to the original apse at Durham, a transept with single east chapel, and eight bays to the nave as at Durham and Dunfermline Abbey. In the late twelfth and early thirteenth century the building was extended to the east with vaulting throughout, and in the late fourteenth century the present lower front was joined to the rest of the building. These later elements introduced the Gothic style with pointed arches. St. Magnus' is the only wholly entire medieval Scottish Cathedral.