Clan Macdonald of Sleat, sometimes known as Clan Donald North and in Gaelic Clann Ùisdein [ˈkʰl̪ˠan̪ˠ ˈuːʃtʲɛɲ], is a Scottish clan and a branch of Clan Donald — one of the largest Scottish clans. The founder of the Macdonalds of Sleat was Ùisdean, or Hugh, a 6th great-grandson of Somerled, a 12th-century Lord of the Isles (Rì Innse Gall). The clan is known in Gaelic as Clann Ùisdein ("children of Ùisdein"), and its chief's Gaelic designation is Mac Ùisdein ("son of Ùisdean"), in reference to the clan's founder. Both the clan and its clan chief are recognised by the Lord Lyon King of Arms, who is the heraldic authority in Scotland.
The Macdonalds of Sleat participated in several feuds with neighbouring clans, most notably the Macleods of Harris & Dunvegan and the Macleans of Duart. The clan also suffered from infighting in the early 16th century, as the leading members of the clan fought and murdered each other.
The clan seems to have grudgingly supported the Royalist cause in the Wars of the Three Kingdoms, and suffered grievously in military defeats against Parliamentarian forces. The clan supported the Jacobite cause in the 1715 rebellion, yet refused to come out for Bonnie Prince Charlie and his father a generation later in 1745. In the early 18th century, the clan's chief was involved in a plan to sell tenants into slavery in the American Colonies. By the late 18th century, the chiefs had alienated themselves from the common clansfolk, when they seated themselves in northern England and rarely visited the old clan lands. The 18th and 19th centuries witnessed the suffering of the common clansfolk, as many were cleared off their lands at the hands of their absentee landlords. Today members and descendants of the clan live all over the world.