Sir Robert Rees Davies, CBE, FBA, FRHistS (6 August 1938 – 16 May 2005) was a Welsh historian.
In 1959 he undertook a two-year postgraduate study of the Duchy of Lancaster's Welsh lordships in the later Middle Ages at Merton College, Oxford under the supervision of K. B.
His 1987 book Conquest, Coexistence and Change: Wales 1063–1415 won him the Wolfson Literary Award for History.
In 1995, he was appointed the Chichele Professor of Medieval History at the University of Oxford and made a fellow of All Souls College.
Davies was appointed a Knight Bachelor for services to history in the Queen's 2005 New Year Honours.