Ronald Buchanan McCallum (28 August 1898 in Paisley, Renfrewshire – 18 May 1973 in Letcombe Regis, Berkshire) was a British historian. He was a fellow (and later Master) of Pembroke College, Oxford, where he taught modern history and politics and was a member of J. R. R. Tolkien's Inklings. McCallum helped popularize the term psephology (statistical analysis of elections).[1]