Sir James Ramsay Montagu Butler, OBE (20 July 1889 – 1 March 1975) was a British politician and academic.

His mother, Montagu Butler's second wife, Agnata Frances Ramsay, attained the highest marks in the Classical Tripos at Cambridge in 1887.

His service led to him being appointed Officer of the Order of the British Empire (OBE) and he was twice mentioned in despatches.

During the Second World War, Butler returned to military service in the Army Intelligence Corps, recruiting many former students including Bernard Willson to work on code breaking at Bletchley Park.

After the conclusion of hostilities, he was appointed editor United Kingdom Military Series of the History of the Second World War by the Prime Minister Clement Attlee.