Gonadal differentiation was histologically investigated in juvenile Labeo victorianus from Lake Victoria. Sex differentiation was marked by division of gonocytes and formation of an ovary-like structure with previtellogenic oocytes. Definitive sex differentiation was by either continued oogenesis, or by atresia of the previtellogenic oocytes with concomitant formation of spermatogonia. Sex development pattern in L. victorianus can, therefore, be categorised as undifferentiated gonochorism.