Homo erectus, meaning "upright man," lived from 1.8 million years ago, if H ergaster is included, or 1.25 million years ago, if excluded. Homo erectus disappeared about 70,000 years ago, and is a member of the homonid family and the Homo genus, which includes modern humans. However, H. erectus was an intermediate form of the genus, falling between the first tool users, early Homo habilis, and present day Homo sapiens. Homo erectus is widely considered to be an ancestor of modern humans.

Homo erectus displayed more humanlike characteristics than its predecessor Homo habilis, being more upright-standing and taller at about 1.8m (5.9 feet) tall instead of 1.3m (4.2 feet). Homo erectus also had a larger brain, though still 75% the size of Homo sapiens. He had smaller teeth, less slope to his forehead, and developed more complex tools. Homo erectus primarily used tools created in the Acheulean style, a type of stone tool industry. The Acheulean era of stone-tooling lasted from about 1.2 million years ago to about 500,000 years ago, although some primitive cultures have used such tools up until 100,000 years ago. Acheulean tooling was represented best by handaxes, chipped on both sides to serve as a more effective means of amplifying the effect Homo erectus could have on his environment. Use of these tools allowed homonids to defend themselves against the largest predators for the first time.

Though he may have tried to control fire, such behavior would not have been typical for Homo erectus, appearing only near the end of his stay on Earth. Traditionally the harnessing of fire is placed at around 100,000 years ago, only 25,000 years before the extinction of Homo erectus. Homo erectus was succeeded by H. heidelbergensis and H. neanderthalensis, who both displayed an increasing ability to make and use tools and generally take control of their environment.

The well-known Java man and Peking man fossils were members of Homo erectus.