The Aterian is a Middle Stone Age stone tool industry centered in North Africa, from Mauritania to Egypt, but also possibly found in Oman and the Thar Desert. The earliest Aterian dates to c. 150,000 years ago, at the site of Ifri n'Ammar in Morocco. However, most of the early dates cluster around the beginning of the Last Interglacial, around 150,000 to 130,000 years ago, when the environment of North Africa began to ameliorate. The Aterian disappeared around 20,000 years ago.

The Middle Stone Age was a period of African prehistory between the Early Stone Age and the Late Stone Age. It is generally considered to have begun around 280,000 years ago and ended around 50–25,000 years ago. The beginnings of particular MSA stone tools have their origins as far back as 550–500,000 years ago and as such some researchers consider this to be the beginnings of the MSA. The MSA is often mistakenly understood to be synonymous with the Middle Paleolithic of Europe, especially due to their roughly contemporaneous time span; however, the Middle Paleolithic of Europe represents an entirely different hominin population, Homo neanderthalensis, than the MSA of Africa, which did not have Neanderthal populations. Additionally, current archaeological research in Africa has yielded much evidence to suggest that modern human behavior and cognition was beginning to develop much earlier in Africa during the MSA than it was in Europe during the Middle Paleolithic. The MSA is associated with both anatomically modern humans as well as archaic Homo sapiens, sometimes referred to as Homo helmei. Early physical evidence comes from the Gademotta Formation in Ethiopia, the Kapthurin Formation in Kenya and Kathu Pan in South Africa.