The King Island emu is an extinct subspecies of emu that was endemic to King Island, in the Bass Strait between mainland Australia and Tasmania. Its closest relative may be the also extinct Tasmanian emu, as they belonged to a single population until less than 14,000 years ago, when Tasmania and King Island were still connected. The small size of the King Island emu may be an example of insular dwarfism. The King Island emu was the smallest of all known emus and had darker plumage than the mainland emu. It was black and brown and had naked blue skin on the neck, and its chicks were striped like those on the mainland. The subspecies was distinct from the likewise small and extinct Kangaroo Island emu in a number of osteological details, including size. The behaviour of the King Island emu probably did not differ much from that of the mainland emu. The birds gathered in flocks to forage and during breeding time. They fed on berries, grass and seaweed. They ran swiftly and could defend themselves by kicking. The nest was shallow and consisted of dead leaves and moss. Seven to nine eggs were laid, which were incubated by both parents.

The emu is a species of flightless bird endemic to Australia, where it is the largest native bird. It is the only extant member of the genus Dromaius and the second-tallest living bird after its African ratite relative, the common ostrich. The emu's native ranges cover most of the Australian mainland. The Tasmanian, Kangaroo Island and King Island subspecies became extinct after the European settlement of Australia in 1788.