Smith, Francis Graham (1923-) is a British astronomer and one of the leading authorities on radio astronomy, the branch of astronomy that studies celestial bodies by measurement and analysis of the electromagnetic radiation they emit in the wavelength range from 1 mm to 30 mm.

Smith received his Ph.D. degree in astronomy in 1952 from Cambridge University, after spending most of World War II (1939–1945) working at the Telecommunications Research Establishment at Malvern. While at Malvern, he gained experience in radar research techniques that later proved invaluable to his career.

After earning his degree, Smith began studying radio waves with astronomer Martin Ryle at Cambridge's Cavendish Laboratory. Their investigations of the sun's emission of radio waves led to a search for similar such phenomena in other celestial bodies. Through techniques developed at Cavendish, Smith and Ryle discovered what seemed to be two other sources of radio waves, but their instruments were able to indicate only the general location of these emissions, one in the constellation Cygnus and the other in the constellation Cassiopeia. In 1951, with help from colleagues, using the powerful Hale telescope at Mount Palomar in southwest California, optical counterparts were pinpointed.

This breakthrough helped launch the development of radio astronomy. Radio astronomy made it possible to investigate celestial phenomena beyond the range of ordinary telescopes. Smith continued to search for and study radio signals over three decades, working in both England and the United States. Among many other contributions, in 1970, he published a theory of “relativistic beaming” to explain the mechanics behind pulsar radio wave emissions. He was appointed director of the Royal Greenwich Observatory in 1976, became director of the Nuffield Radio Astronomy Laboratories at Jodrell Bank in 1981, and was named Astronomer Royal in 1982. He was knighted in 1986. He has written many well-regarded books on radio astronomy, further establishing the importance of the field.