Sir Robert Charles Kirkwood Ensor (16 October 1877 – 4 December 1958) was a British writer, poet, journalist, liberal intellectual and historian. He is best known for England: 1870-1914 (1936), a volume in the Oxford History of England series edited by George Clark. He was commissioned in 1937 to write a sequel to his volume of the Oxford History of England but he resumed his journalism during the Second World War with a weekly column on foreign affairs in the Sunday Times. The book, a volume covering the years 1914 to 1945, was eventually written by A.J.P. Taylor.