James A. "Jim" Chamberlin (May 23, 1915 – March 8, 1981) was a Canadian aerodynamicist who contributed to the design of the Canadian Avro Arrow, NASA's Gemini spacecraft and the Apollo program. In addition to his pioneering air and space efforts, he is often cited as an example of Canadian brain drain to the U.S. In the early 1960s, he was one of the key people that proposed and moved that Lunar Orbit Rendezvous (LOR) was the best option for landing a crew on the Moon, the method eventually used on Apollo lunar landing missions. He left NASA in 1970 and worked for McDonnell Douglas, in their Houston offices, until his death in 1981.