William MacIntyre (circa 1791/1792–March 4, 1857) was a British physician known for publishing the first case report of multiple myeloma in 1850.
MacIntyre graduated from the University of Edinburgh in 1811.
He then established a successful practice, eventually in Harley Street, London. He was also a consultant to the Western General Dispensary and Metropolitan Convalescent Institution. He became a fellow of the Royal College of Physicians in 1851.