Mary Campbell, Countess of Argyll (1628 – May 1668), formerly Lady Mary Stuart (or Stewart), was the wife of Archibald Campbell, 9th Earl of Argyll. Lady Mary was born at Darnaway Castle, Elginshire, a daughter of James Stuart, 4th Earl of Moray, and his wife, the former Lady Margaret Home. On 13 May 1650, she married the future earl, then known as Lord Lorne, at Canongate, Edinburgh. Their children were: In 1663, Lord Lorne regained the title and estates which his father had lost when he was convicted of treason and executed in 1661. Lorne became Earl of Argyll, and his wife became countess.