Homo habilis is a species of the Hominini tribe, which lived from approximately 2.33 to 1.44 million years ago, during the Gelasian Pleistocene period.

While there has been scholarly controversy regarding its placement in the genus Homo rather than the genus Australopithecus, its brain size has been shown to range from 550 cm3 to 687 cm3, rather than from 363 cm3 to 600 cm3 as formerly thought.

In its appearance and morphology, H. habilis is the least similar to modern humans of all species in the genus Homo (except the equally controversial H. rudolfensis), and its classification as Homo has been the subject of controversial debate since its first proposal in the 1960s.

H. habilis was short and had disproportionately long arms compared to modern humans; however, it had a less protruding face than the australopithecines from which it is thought to have descended.

H. habilis had a cranial capacity slightly less than half of the size of modern humans.

Despite the ape-like morphology of the bodies, H. habilis remains are often accompanied by primitive stone tools (e.g.

Olduvai Gorge, Tanzania and Lake Turkana, Kenya).Homo habilis has often been thought to be the ancestor of the more gracile and sophisticated Homo ergaster, which in turn gave rise to the more human-appearing species, Homo erectus.

Debates continue over whether all of the known fossils are properly attributed to the species, and some paleoanthropologists regard the taxon as invalid, made up of fossil specimens of Australopithecus and Homo.

New findings in 2007 seemed to confirm the view that H. habilis and H. erectus coexisted, representing separate lineages from a common ancestor instead of H. erectus being descended from H. habilis.

An alternative explanation would be that any ancestral relationship from H. habilis to H. erectus would have to have been cladogenetic rather than anagenetic (meaning that if an isolated subgroup population of H. habilis became the ancestor of H. erectus, other subgroups remained as unchanged H. habilis until their much later extinction).