Ronald Edmond Balfour (1904 – 10 March 1945) was a British medieval historian and a fellow of King's College, Cambridge.
Balfour was educated at Eton and King's, Cambridge, matriculating in 1922. He was elected a Fellow of King's College in 1928 and Lecturer in History in 1930.
During the Second World War he held administrative posts with the French section of the Ministry of Information. In 1941 he was commissioned in the King's Royal Rifle Corpsthen worked in Winchester and York interviewing recruits and finally with the Monuments, Fine Arts and Archives section (MFAA) of the Supreme Headquarters Allied Expeditionary Force. He was killed by a shell-burst while operating beyond the Allied front line at Kleve (Cleves), seeking out artworks to be protected from war damage. He is buried in Reichswald Forest War Cemetery.
He bequeathed his personal library of 8,000 books to be divided between the Cambridge University Library and the King's College Library.
In the 2014 film The Monuments Men, he is loosely represented by fictional British officer "Donald Jeffries", played by Hugh Bonneville.