They are found in the Moluccas (Spice Islands - a group of islands in the eastern part of the Malay Archipelago, part of Indonesia), New Guinea and northeastern Australia.

They are most abundant on New Guinea, with only the genus Lycocorax and Semioptera being endemic to the Moluccas. However, two species of Ptiloris are endemic to Australia. One is found exclusively in New Guinea, the other in New Guinea and Australia. Many species of birds of paradise occupy very restricted habitats, e.g., the Black sicklebill, found only in the middle mountains of New Guinea (1000-2000 m), and the Brown sicklebill is endemic to the Indonesian islands of Batanta and Waigeo.