Sir Donald Maclean (1864-1932) was a Liberal Member of Parliament for Bath (1906-1910), Peebles and Selkirk (1910-1918), Peebles and South Midlothian (1918-1922), and Northern Division of Cornwall (1929-1932) and served as President of the Board of Education (1931-1932). He led the Liberals in the House of Commons from 1918-1922, and served as nominal Leader of the Opposition, as the Liberal leader, Herbert Henry Asquith had been turned out of parliament, while Labour had no official leader and Sinn Fein refused to participate in normal parliamentary government.

His son was the spy, Donald Duart Maclean.