The Little long-tailed dunnart (Sminthopsis dolichura) is a dunnart that was, along with Gilbert's dunnart, described in 1984. The length from snout to tail is of which head and body are and tail long. Hind foot size is, the ear length is and the weight is .
There are two separate areas of habitation for this species, but no subspecies have been identified. The Western Australia distribution is in the northern Goldfield's and Geraldton hinterland, northwest coast, southwest coast and western plateau. The South Australian area includes the coastal areas of the Great Australian Bight on the Nullarbor Plain, Eyre Peninsula west of Port Augusta. Habitat the species prefers include dry sclerophyll, forest, semi-arid woodlands, mallee, (tall, tall open and low open) shrublands and open heath vegetation.
The species is nocturnal with males having a large home range, an adaptation to exploiting various habitats from one season to another. Females breed as early as 5–8 months and then only between March and August. Males can breed at 4–5 months. The joeys are weaned during September–December or when 5 grams. The lifespan of females is approximately two years and males just over one year.
Primarily an insect eater, the little long-tailed dunnart will also consume small reptiles, amphibians and mammals.