Stereognathus is a genus of tritylodontid cynodont from the Middle Jurassic of the United Kingdom. There are two named species: S. ooliticus, named after the Great Oolite deposits of England, and S. hebridicus, named after the Hebrides in Scotland, where it was found. Despite being the first tritylodontid genus found and named, Stereognathus remains poorly represented, being known mainly from isolated molar teeth. There is however one holotype fragment of maxilla with three damaged molars, and a second fragment of maxilla with four sets of molar roots.