The six species of the genus Certhia constitute the family Certhiidae (order Passeriformes). The best known is C. familiaris, a 13-centimetre- (5-inch-) long streaky brown-and-white bird found in woodlands across the Northern Hemisphere; it is known as treecreeper in Europe and brown creeper in North America. Its tail is stiffened and serves as a prop against the tree. Its nest, a soft cup within a mass of rootlets, is usually placed behind a slab of bark and contains three to nine eggs.

The six species of Climacteris, known as Australian treecreepers, constitute the family Climacteridae, which is sometimes considered a subfamily of the Sittidae (nuthatches (nuthatch)) or the Meliphagidae (honeyeaters (honeyeater)); formerly, these creepers were included in the family Certhiidae. The Australian treecreepers have brush-tipped tongues and behave rather like honeyeaters, although they resemble certhiids in their drab streaky plumage. As in nuthatches, the tail is not stiffened. The nest, made in a tree hollow, contains one to four eggs. Climacterids are virtually confined to Australia; one species ranges to New Guinea.

Rhabdornis species (see creeper) are also sometimes placed in the Climacteridae.