Clan MacDougall is a Highland Scottish clan, historically based in and around Argyll. The Lord Lyon King of Arms, the Scottish official with responsibility for regulating heraldry in Scotland, issuing new grants of coats of arms, and serving as the judge of the Court of the Lord Lyon, recognizes under Scottish law the Chief of Clan MacDougall. The MacDougall chiefs share a common ancestry with the chiefs of Clan Donald in descent from Somerled of the 12th century. In the 13th century the Clan MacDougall whose chiefs were the original Lords of Argyll and later Lords of Lorne was the most powerful clan in the Western Highlands. During the Wars of Scottish Independence the MacDougalls sided with the Clan Comyn whose chiefs rivaled Robert the Bruce for the Scottish Crown and this resulted in clan battles between the MacDougalls and Bruce. This marked the MacDougall's fall from power and led to the rise of their relatives, the Clan Donald, who had supported Bruce and also the rise to power of the Clan Campbell who were then the habitual enemies of the MacDougalls and later of Clan Donald.

A Scottish clan is a kinship group among the Scottish people. Clans give a sense of shared heritage and descent to members, and in modern times have an official structure recognised by the Court of the Lord Lyon, which regulates Scottish heraldry and coats of arms. Most clans have their own tartan patterns, usually dating from the 19th century, which members may incorporate into kilts or other clothing.