Herto Man refers to human remains (Homo sapiens) discovered in 1997 from the Upper Herto member of the Bouri Formation in the Afar Triangle, Ethiopia. The remains have been dated as between 154,000 and 160,000 years old. The discovery of Herto Man was especially significant at the time, falling within a long gap in the fossil record between 300 and 100 thousand years ago and representing the oldest dated H. sapiens remains then described.

In the original description paper, these 12 (at minimum) individuals were described as falling just outside the umbrella of "anatomically modern human". Thus, Herto Man was classified into a new subspecies as "Homo sapiens idaltu" (Afar: Idaltu "elder"). It supposedly represented a transitional morph between the more archaic H. (s.?) rhodesiensis and H. s. sapiens (that is, a stage in a chronospecies). Subsequent researchers have rejected this classification. The validity of such subspecies is difficult to justify because of the vague definitions of "species" and "subspecies", especially when discussing a chronospecies, as the exact end-morphology and start-morphology of the ancestor and descendant species are inherently unresolvable.

Herto Man produced many stone tools which can fit into the vaguely defined "Transitional Acheulean", the long-lasting cultural tradition with both characteristically Acheulean (made by archaic humans) and Middle Stone Age (made by modern humans) tools. They seem to have been butchering mainly hippo, but also bovines, in a lakeside environment. The three most complete skulls (one a 6- to 7-year-old child) bear manmade cut marks and other alterations, which could be evidence of mortuary practices like excarnation.

Fossils of Herto Man were first recovered in 1997 from the Upper Herto Member of the Bouri Formation in the Middle Awash site of the Afar Triangle, Ethiopia. The materials are: BOU-VP-16/1, a nearly complete skull missing the left skullcap; BOU-VP-16/2, skull fragments; BOU-VP-16/3, a parietal bone fragment; BOU-VP-16/4, a parietal fragment; BOU-VP-16/5, a nearly complete skull of a 6- or 7-year old; BOU-VP-16/6, a right upper molar; BOU-VP-16/7, a parietal fragment; BOU-VP-16/18, parietal fragments; BOU-VP-16/42, an upper premolar; and BOU-VP-16/43, a parietal fragment. Further excavation has yielded a total of 12 individuals.

This region of the world is famous for yielding a series of ancient human and hominin species stretching as far back as 6 million years. In 2003, using argon–argon dating, the Upper Herto Member was dated to 160 to 154 thousand years ago. The Herto Man was a major fossil find as, at the time, there was a significant gap in the human fossil record between 300 and 100 thousand years ago, obfuscating the evolution of "Homo (sapiens?) rhodesiensis" into H. s. sapiens.

By the time Herto Man was discovered, based on genetic analyses and the fossil record after 120,000 years ago, it was largely agreed that modern humans H. s. sapiens evolved in Africa (recent African origin model), but it was debated if this was a continent-wide or localised process. In regard to the localised model, the antiquity of the Herto Man and the several similar specimens of presumably equal or even older age distributed across East Africa shifted the focus to that region. In 2017, the Jebel Irhoud remains were dated to 315,000 years ago, making them the oldest specimens classified as H. sapiens. Because this date overlaps with "H. rhodesiensis", the Irhoud remains also demonstrate that these transitional morphs, including Herto Man, represent a rapid evolution of the sapiens face, with gradual modifications to the braincase among populations distributed across Africa, beginning as early as 300,000 years ago.

In a simultaneously published paper, anthropologists Tim D. White, Berhane Asfaw, David DeGusta, Henry Gilbert, Gary D. Richards, Gen Suwa, and Francis Clark Howell described the material as just barely outside what is considered an "anatomically modern human" (AMH), beyond the range of variation for any present-day human. They instead considered the earliest "AMHs" specimens from Klasies River Caves, South Africa, or Qafzeh cave, Israel. They did this by comparing BOU-VP-16/1 with the Qafzeh 6 skull, the La Ferrassie 1 skull (a male Neanderthal, H. (s.?) neanderthalensis), the Kabwe 1 skull ("H. (s.?) rhodesiensis"), and 28 present-day male skulls. Consequently, they classified Herto Man as a new palaeosubspecies of H. sapiens as "H. s. idaltu" (with the presumed male BOU-VP-16/1 as the holotype), which represents an intermediary morph between "H. (s.?) rhodesiensis" and present-day H. s. sapiens. The name comes from the local Afar language idàltu "elder". Similarly transitional specimens (at the time, not well-dated) tentatively assigned to "late archaic H. sapiens" had been reported from Ngaloba, Tanzania; Omo, Ethiopia; Eliye Springs, Kenya; and Jebel Irhoud, Morocco.

In another simultaneously published paper, British physical anthropologist Chris Stringer doubted the validity of "H. s. idaltu", saying the material was similar to some Late Pleistocene Australasian specimens. White et al. made note of this, but still considered Herto Man "clearly distinct". In 2011, American anthropologists Kyle Lubsen and Robert Corruccini compared BOU-VP-16/1 with Skhul 5 from Es-Skhul Cave, Israel (temporally close to the Qafzeh material), and instead reported these two skulls are closely allied with each other. That is, their analysis found no support for Herto Man's position as a transitional morph, nor the nomen idaltu. In 2014, anthropologists Robert McCarthy and Lynn Lucas considered a much larger sample than White et al.—using several specimens representing "archaic Homo", Neanderthal, "early modern H. s. sapiens", and Late Pleistocene H. s. sapiens—and arrived at the same conclusion as Lubsen and Corruccini. Citing these two studies, in 2016, Stringer, in his review of literature regarding the derivation of H. s. sapiens, said the name idaltu, "does not seem justified."