Ivan Terence Sanderson (January 30, 1911 – February 19, 1973) was a British biologist and writer born in Edinburgh, Scotland, who became a naturalized citizen of the United States. Along with Belgian-French biologist Bernard Heuvelmans, Sanderson was a founding figure of cryptozoology, a pseudoscience and subculture. Sanderson authored material on paranormal subjects and wrote fiction under the pen name Terence Roberts.