The genus Ptilomera is revised for New Guinea and nearby islands. Four previously described taxa are redescribed and discussed: P. aello Breddin, P. papuensis Hungerford & Matsuda, P. breddini Hungerford & Matsuda, and P. cheesmanae Hungerford & Matsuda, the latter newly elevated from subspecies to full species rank. Eighteen new species are described as follows: P. waigeo from Waigeo Island, P. misoolensis from Misool Island, P. yapenana from Yapen Island, P. arfak from the Vogelkop Peninsula of Irian Jaya, P. timika from southern Irian Jaya, P. etna from western central Irian Jaya, P. iriana from north central Irian Jaya, P. wapoga from north central Irian Jaya, P. kiunga from southwestern Papua New Guinea, P. omo from southern central Papua New Guinea, P. kutubu from the southern highlands of Papua New Guinea, P. jimi from the central highlands of Papua New Guinea, P. wewak from northern Papua New Guinea, P. morobe from northeastern Papua New Guinea, P. biroi from northeastern Papua New Guinea, P. insularis from Umboi Island, P. novabrittanica from New Britain, and P. bismarckensis from New Ireland. Keys to all species occurring in the New Guinea region are provided for both males and females, accompanied by range maps, and figures of the male genitalic complex, male parameres, male endosoma, and female terminal abdomen in lateral view.