Three species of Rogadius Jordan & Richardson, 1908, with antrorse preopercular spines have been previously known from the western Indian Ocean (WIO). A new species, Rogadius fehlmanni, is described from eight specimens taken at three localities off Somalia. It is distinguished from its congeners by the following combination of characters: lower edge of preopercle developed as a stout antrorse spine; preocular spines 2–4, usually with accessory spines on base of the largest; 5–6 diagonal scale rows between second dorsal fin and lateral line; pelvic fins blackish, lacking individual dark spots. A key separating the four species is provided.