Thrinaxodontidae is an extinct family of cynodonts that includes the genera Thrinaxodon, Nanictosaurus, Nanocynodon, and Novocynodon, and possibly Bolotridon and Platycraniellus. All thrinaxodontids share a bony secondary palate. Thrinaxodontids are basal members of the cynodont clade Epicynodontia. Some studies consider the family a paraphyletic group, representing an evolutionary grade of basal epicynodonts rather than an actual clade.