MacLean, also spelt Maclean and McLean, is a Gaelic surname Mac Gille Eathain, or, Mac Giolla Eóin in Irish Gaelic), Eóin being a Gaelic form of Johannes (John). The clan surname is an Anglicisation of the Scottish Gaelic "Mac Gille Eathain", a patronymic meaning "son of Gillean". Gillean means "the Servant of [Saint] John [the Baptist]"), named for Gilleathain na Tuaidh, known as "Gillian of the Battleaxe", a famous 5th century warrior.

Eachan Reaganach and his brother Lachlan were descended from Gilleathain na Tuaidh, and are the progenitors of the clan. The family grew very powerful throughout the Hebrides and Highlands through alliances with the Catholic Church in Scotland in the 9th century, the MacDonalds in the 13th century, and the MacKays and MacLeods in the 16th century. Other spellings of the name include McClean, MacLaine, McLaine, McLain, MacLane, and many others.

Duart Castle is the seat of Clan MacLean.