William Conrad Costin, MC (19 May 1893 – 6 October 1970)[1] was President of St John's College, Oxford, from 1957 to 1963.
Costin was educated at Reading School[2] and St John's College, Oxford. He served in the Great War with the Gloucestershire Regiment. He was Proctor of Oxford University in 1935. He wrote: Great Britain and China, 1833–1860, 1937; The Law and Working of the Constitution: Documents, 1660–1914, 1952; and History of St John’s College, 1598–1860, 1958.[3]