Clan Campbell is a Highland Scottish clan. Historically one of the largest, most powerful and most successful of the Highland clans, their lands were in Argyll and the chief of the clan became the Earl and later Duke of Argyll.
The earliest attested Campbell is Gilleasbaig of Menstrie (floruit 1260s), father of Cailean Mór, from whom the chiefs of the clan are thought to have taken their style MacCailean Mór. The byname kambel is recorded at this time. Fanciful reconstructions derive it from the Spanish de Campo Bello, but the likely source is the caimbeul, an Early Modern Irish or Gaelic by name meaning wry mouth, crooked mouth or twisted mouth, which refers to "the man whose mouth inclined a little on one side. Regarding the earlier ancestors of Clan Campbell, there is good evidence that the Campbells themselves traced their descent from an earlier kindred known as the Mac Duibne, or perhaps the Uí Duibne. It has been suggested that the family's early landholdings, around Menstrie, and in Cowal, were related to the partition of the Earldom of Menteith in 1213, and that Gilleasbuig may have been a kinsman of Muireadhach I, Earl of Menteith. The lands around Loch Awe, which would later form the core of their possessions, were not held at an early date.