Arthur Roy Clapham, CBE FRS (24 May 1904 – 18 December 1990), was a British botanist. Born in Norwich and educated at Downing College, Cambridge, Clapham worked at Rothamsted Experimental Station as a crop physiologist (1928–30), and then took a teaching post in the botany department at Oxford University. He was Professor of Botany at Sheffield University 1944–69. He coauthored the Flora of the British Isles. In response to a request from Arthur Tansley, he coined the term ecosystem in the early 1930s.