Archibald Alexander McBeth Duncan, FBA, FRHistS, FRSE (born 17 October 1926) is a Scottish historian.
From 1962 to 1993 he was Professor of Scottish History and Literature at the University of Glasgow. On giving up his professorship, he became Clerk of Senate and Dean of Faculties, retiring from the University in 2000. Since 2001 he has been Emeritus Professor of Scottish History and Literature.
He continues to publish on the history of Scotland in the Middle Ages.
- Scotland: The Making of the Kingdom. Edinburgh: Edinburgh University Press, 1973.
- The Kingship of the Scots: Succession and Independence 842–1292. Edinburgh: Edinburgh University Press, 2002.