The black-backed bittern, also known as the black-backed least bittern or Australian little bittern, is a little-known species of heron in the family Ardeidae found in Australia and vagrant to southern New Guinea. Formerly lumped with the little bittern, it is one of the smallest herons in the world.

Ixobrychus is a genus of bitterns, a group of wading bird in the heron family Ardeidae. It has a single representative species in each of North America, South America, Eurasia, and Australasia. The tropical species are largely resident, but the two northern species are partially migratory, with many birds moving south to warmer areas in winter.