A revision of six sections of the genus Bulbophyllum (Orchidaceae): sect. Adelopetalum (mainly occurring in Australia), sect. Lepanthanthe, sect. Macrowris, sect. Pelma, sect. Peltopus, and sect. Unicfera (all mainly occurring in New Guinea). Together these include 110 species and 9 subspecies. Forty-seven species and 4 subspecies are new. Keys to the species, as well as synonymy, descriptions and illustrations of each species are provided. Some aspects of the morphology of the plants are discussed.