The Brown Treecreeper is the largest of Australia's treecreepers. It is mostly pale brown in plumage. Birds of northern Queensland are darker brown. The head, throat and upper breast are pale greyish-brown, while the lower breast and belly are strongly streaked with black and buff. In flight, a buff stripe can be seen in the wing. The sexes are similar, except females have rufous edges to the feathers of the upper breast, while in the male these edges are black. Young Brown Treecreepers resemble the adults, but are duller, have less obvious stripes on the underparts and the lower belly is a pale rufous colour.