Odontanthias hensleyi, a new species of anthiine serranid fish, is described from four specimens collected off the west coast of Puerto Rico in Mona Passage. This is the first Atlantic record for the genus Odontanthias, heretofore known from 13 Indo-Pacific species. The new species is distinguished from all other species of Odontanthias by the following combination of characters: 15 soft rays in the dorsal fin, 18 pectoral fin rays, vomerine tooth patch subquadrangular to diamond-shaped without posterior prolongation, pelvic fin and caudal fin lobes very well produced, and coloration (side of head with two bright yellow stripes; pelvic, anal and caudal fins bright yellow).