Oxyrhopus formosus is a neotropical snake of the family Dipsadidae. Its distribution is not fully understood, because of inaccurate identifications and confusion with other Oxyrhopus species. It has been reported from Brazil, Colombia, and Peru. Reports from the Guiana region are based on misidentified O. occipitalis. Oxyrhopus formosus are robust, the head is entirely yellow, and adults are red with prominent black bands; O. occipitalis are slender, the snout is yellow and the top of head is brown, and adults are red with faint crossbands.