Tasmaniosaurus ('Lizard from Tasmania') is an archosaur of the family Proterosuchidae, known from the Knocklofty Formation (Early Triassic) of West Hobart, Tasmania, Australia. It is Australia's most complete Triassic reptile fossil; the entire skeleton has been preserved. The type species is T. triassicus. The genus was first described in 1978, but was first named as a nomen nudum in 1974.