The Spotted tailed Quolls fur ranges orange brown to reddish brown to dark chocolate brown to almost black, with white spots. Its underbelly is often is often cream to white This species of Quoll is the only one in which the pattern of white spots on the body is continued into the tail. Its face is made up of a moist pink nose, pointy ears, a thick snout and a mouth that can open wide to show a lot of sharp teeth Males measuring up to 130 cm long and 4 kg in weight.
Females are significantly smaller than males.
They will stay in the pouch for 7 weeks and then when furred will live in the grass lined den still suckling their mothers milk for a further 6 weeks. This allows the female to forage for food.