The mountain swiftlet (Aerodramus hirundinaceus) is a species of swift in the family Apodidae. It is endemic to the island of New Guinea and the nearby islands of Karkar, Yapen and Goodenough. It was once placed in the genus Collocalia but has been moved, with many others, to Aerodramus. The species is divided into three subspecies, with the nominate, A. h. hirundinacea ranging over most of New Guinea, the subspecies A. h. excelsus occurring over 1600 m in the Snow Mountains and Cartenz peaks of Irian Jaya and A. h. baru being restricted to Yapen Island. It occurs in alpine areas from 500 m to the treeline. Its natural habitat is tropical moist montane forests and other mountainous habitats in New Guinea. It also occurs in lower numbers in the lowlands near hills.