The Triangulum Galaxy is a spiral galaxy approximately 3 million light years distant in the constellation Triangulum. It is catalogued as Messier 33, and is sometimes informally referred to as the Pinwheel Galaxy, a moniker it shares with Messier 101.

The Triangulum Galaxy is a member of the Local Group of galaxies, which includes the Milky Way Galaxy, the Andromeda Galaxy and about 30 other smaller galaxies.