Species of the hermit crab genus Diogenes that either were described by Herbst or attributed to him have been reevaluated, and the ambiguity, both in matters of species authorship and species identity, have been assessed. The species that Herbst incorrectly identified as Cancer diogenes Linnaeus has not, to date, received an available name; therefore, the new name, Diogenes alias, is proposed. The actual holotype of D. miles Fabricius has been identified, and a neotype has been selected for D. custos Fabricius. The “true” D. custos has proved to be the senior synonym of D. affinis Henderson, and the misinterpreted D. custos of numerous authors have been reassigned to D. dubius Herbst. Diogenes platvoeti McLaughlin and Clark (a new name for D. intermedius De Man, non D. pugilator intermedius Bouvier) has been found to be a junior synonym of D. hainanica Wang and Dong and both taxa are synonymous with D. mixtus Lanchester.