The native Nearctic species of the family Sparassidae are revised. Eight synonymies are proposed, reducing the number of species to five: Olios schistus Chamberlin 1919, O. scepticus Chamberlin 1924 and O. positivus Chamberlin 1924 with O. peninsulanus Banks 1898; O. albinus Fox 1937 and O. foxi Roewer 1951 with O. naturalisticus Chamberlin 1924. Olios concolor Keyserling 1884 and O. pragmaticus Chamberlin 1924 are removed from the synonymy of O. fasciculatus Simon 1880 and synonymized with O. giganteus Keyserling 1884. All species currently included in the genus Olios Walckenaer 1837 are redescribed and illustrated, and new distribution records are presented. Comparisons between these species and the type species of the genus Olios, Olios argelasius (Walckenaer 1805), shows that none of them are congeneric and that true Olios does not occur in the Nearctic region. Nevertheless, the correct placement of these species in new genera will only be possible after a more thorough revision of the Nearctic and Neotropical fauna, especially that of Mexico and Central America.