Richard Brent Tully (born March 9, 1943) is a Canadian-born American astronomer at the Institute for Astronomy in Honolulu, Hawaii.
Born in Toronto, Ontario, and raised in Vancouver, British Columbia, Tully's specialty is the astrophysics of galaxies.
With J. Richard Fisher, he proposed the Tully–Fisher relation, which shows that the luminosity of a galaxy and the orbital velocities of its stars are correlated.
A particularly remarkable discovery was that our Milky Way galaxy lies adjacent a vast underdense region that Tully called the Local Void.
A more extended compilation of 30,000 galaxies within a cube of diameter 700 million light years centered on Earth can be visually navigated with the planetarium computer software Starry Night Pro, where the data is called the Tully Database.