Eucnemesaurus (/juːkˌniːmɨˈsɔrəs/; meaning "good tibia lizard", for its robust tibiae) is a basal sauropodomorph dinosaur genus usually considered to be a synonym of Euskelosaurus. Recent study by Yates (2006), however, indicates that it is valid and the same animal as putative "giant herrerasaurid" Aliwalia.
Eucnemesaurus was named in 1920 by Egbert Cornelis Nicolaas van Hoepen. The type species is Eucnemesaurus fortis. The specific name means "strong" in Latin. It is based on holotype TrM 119, a partial skeleton including vertebrae, part of a pubis, a femur, and two tibiae. The remains were found by Van Hoepen in the late Carnian-early Norian-age Upper Triassic Lower Elliot Formation of the Slabberts district, Orange Free State, South Africa.
Yates assigned the genus to the new family Riojasauridae, with Riojasaurus, usually regarded as a melanorosaurid.