A distinctive new species of the colubrid snake genus Heteroliodon is described from the deciduous dry forest of Montagne des Français, near the northern tip of Madagascar. The new species is characterized by stout habitus, low number of ventral scales, long relative tail length, high number of infralabial scales, and absence of a light colored vertebral stripe. The limestone massif of Montagne des Français appears to be an important center of endemism for Madagascan biota and should, therefore, be included in Madagascar's network of nature reserves.