SummaryThe Australian treecreepers of the genusClimacterisshow little affinity with the typical treecreepers Certhiidae and have been separated as a family, the Climacteridae. It has been suggested that they may be related to the Australian warblers Acanthizinae; but they appear to show affinities with honeyeaters Meliphagidae. A comparative examination of a range of characters shows that they resemble the honeyeaters in many of these, resemble the warblers only in some aspects of plumage pattern, and evidence of relationship from other characters is inconclusive. It is suggested, on the basis of present information, that the honeyeaters are the most likely group to have given rise to the Australian treecreepers, and that rather little adaptation would have been needed for this.