The Paleolithic or Palaeolithic Age, Era, or Period, or Old Stone Age, is a prehistoric era distinguished by the development of the first stone tools, and covers roughly 99% of human history.

It extends from the introduction of stone tools by hominids such as Homo habilis 2.5 or 2.6 million years ago, to the introduction of agriculture and the end of the Pleistocene around 10,000 BCE.

The Paleolithic era ends with the Mesolithic, in Western Europe, and with the Epipaleolithic in areas not affected by the Ice Age (such as Africa).

During the Paleolithic, humans group together in small societies such as bands, and subsist by gathering plants and hunting or scavenging wild animals.

The Paleolithic is characterized by the use of knapped stone tools, although humans also use wood and bone tools.

Other organic commodities are adapted for use as tools, including leather and vegetable fibers; however, due to their nature, these have not been preserved to any great degree.

Surviving artifacts of the Paleolithic era are known as Paleoliths.

Humankind gradually evolves from early members of the genus Homo such as Homo habilis — who use simple stone tools — into fully behaviorally and anatomically modern humans (Homo sapiens sapiens) during the Paleolithic era.During the end of the Paleolithic, specifically the Middle and or Upper Paleolithic, humans begin to produce the earliest works of art and engage in religious and spiritual behavior such as burial and ritual.

The climate during the Paleolithic consists of a set of glacial and interglacial periods in which the climate periodically fluctuates between warm and cool temperatures.