Earl of Orkney, historically Jarl of Orkney, is a title of nobility encompassing the archipelagoes of Orkney and Shetland, which comprise the Northern Isles of Scotland. Originally founded by Norse invaders, the status of the rulers of the Northern Isles as Norwegian vassals was formalised in 1195. Although the Old Norse term jarl is etymologically related to "earl", and the jarls were succeeded by earls in the late 15th century, a Norwegian jarl is not the same thing. In the Norse context the distinction between jarls and kings did not become significant until the late 11th century and the early jarls would therefore have had considerable independence of action until that time. The position of Jarl of Orkney was eventually the most senior rank in medieval Norway except for the king himself.

Scandinavian Scotland was the period from the 8th to the 15th centuries during which Vikings and Norse settlers, mainly Norwegians and to a lesser extent other Scandinavians, and their descendants colonised parts of what is now the periphery of modern Scotland. Viking influence in the area commenced in the late 8th century, and hostility between the Scandinavian earls of Orkney and the emerging thalassocracy of the Kingdom of the Isles, the rulers of Ireland, Dál Riata and Alba, and intervention by the crown of Norway were recurring themes.