Both sexes of Sigmactenus timorensis n. sp. are described from Rattus tanezumi and Rattus exulans collected in West Timor, Indonesia. The true host presumably is a native murine rat such as the extant, endemic Rattus timorensis or 1 of several extinct, endemic Timorese rats. Analyses of new collections of Sigmactenus cavifrons and Sigmactenus toxopeusi from New Guinea demonstrate that these fleas show considerable morphological variation. We propose that they represent a single species with the name S. toxopeusi having priority. New collections of Sigmactenus werneri from the Philippines expand the known hosts and geographical distribution of this flea.