Colin Grant Clark (November 2, 1905 - September 4, 1989) was a British economist and statistician who worked in both the United Kingdom and Australia, and who pioneered the use of the gross national product ("GNP") as the basis for studying national economies.

Colin Clark was born in London and educated at the Dragon School in Oxford, then at Winchester College, then at Brasenose College Oxford where he graduated in Chemistry in 1928. After graduation he worked as a research assistant with William Beveridge at the London School of Economics (1928-29) and then with Sir Alexander Carr-Saunders and Allyn Young at the University of Liverpool (1929-30). During this time he ran unsuccessful campaigns for Labour in the parliamentary seat of North Dorset (1929), and later for Liverpool (1930) and Wavertree and South Norfolk (1935). In 1930 he was appointed a research assistant to the Economic Advisory Council newly convened by Prime Minister Ramsay McDonald. He resigned shortly after his appointment, after being asked to write a background memorandum to make a case for protectionism, though he had sufficiently impressed one of the council members (John Maynard Keynes) to secure an appointment as a lecturer in statistics at Cambridge University.

He was a lecturer in Statistics in Cambridge from 1931 to 1938 where he completed three books: "The National Income 1924-31" (1932), "The Economic Position of Great Britain" (jointly with A.C Pigou) (1936) and "National Income and Outlay" (1937). His first book was sent to the publisher Daniel Macmillan with a recommendation from Keynes: