An estimated 2 trillion+ galaxies occupy the observable universe. On the order of 100,000 galaxies make up the Local Supercluster, and about 51 galaxies are in the Local Group (see list of nearest galaxies for a complete list).

The first attempts at systematic catalogues of galaxies were made in the 1960s, with the Catalogue of Galaxies and Clusters of Galaxies listing 29,418 galaxies and galaxy clusters, and with the Morphological Catalogue of Galaxies, a putatively complete list of galaxies with photographic magnitude above 15, listing 30,642. In the 1980s, the Lyons Groups of Galaxies listed 485 galaxy groups with 3,933 member galaxies. Galaxy Zoo is a project aiming at a more comprehensive list: launched in July 2007, it has classified over one million galaxy images from The Sloan Digital Sky Survey, The Hubble Space Telescope and the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey.

This is a list of galaxies that are well known by something other than an entry in a catalog or list, or a set of coordinates, or a systematic designation.

This is a list of galaxies that are visible to the naked eye, for at the very least, keen-eyed observers in a very dark-sky environment that is high in altitude, during clear and stable weather.

This is a list of galaxies that became prototypes for a class of galaxies.