The spot-tailed quoll is mostly found down the eastern coastal fringe of Australia. Populations range from south east Queensland, to New South Wales and Victoria, and are found throughout Tasmania with a small range in far-north Queensland.
Quolls are found in a variety of habitats including eucalypt forest and woodlands, coastal heathland, rain forests and rocky headlands. They prefer undisturbed, diverse habitats, as they contain hollow trees and logs, rock crevices and caves which the quolls can use as dens and breeding sites.
Quoll numbers are declining. The major cause is land clearing, with subsequent loss and fragmentation of habitat. Other factors are competition for prey from cats and foxes, and poisoning by 1080 (fox) baits.