A peltast was a type of light infantry in Ancient Greece who often served as skirmishers. Peltasts carrried a crescent-shaped wicker shield called pelta (latin: peltarion) as their only protection, hence their name. Their weapons consisted of several javelins, often with throwing straps to increase standoff power. In the Archaic period the Greek martial tradition had been focused almost exclusively on the heavy infantry or hoplites. Peltast became gradually more important in Greek warfare, in particular during the Peloponnesian War. The Athenian general Iphicrates destroyed a Spartan phalanx using mostly peltasts.

Peltasts couldn't afford the panoply of a hoplite and were recruited from the poorer strata of society. Usually they were mercenaries. They made up the largest part of the forces of the Aetolian League and Achaean League.

Peltasts were reputedly Thracian in origin. On vases and other images they are generally depicted with the costume of Thrace. However, many of them were propably poorer soldiers from other parts of Greece.