The Gaesatae or Gaesati (Latin Gaesati, Greek Γαισάται) were a group of Gallic mercenary warriors who lived in the Alps and near the river Rhône in the 3rd century BC. They fought against the Roman Republic at the Battle of Telamon in 225 BC, and later in 221 BC.
Polybius and Plutarch describe the Gaesatae as mercenaries called in from Transalpine regions by the Insubres and the Boii, who enticed them with promises of considerable plunder. They disappear from historical accounts after the campaigns in Cisalpine Gaul, around the time the Allobroges begin to appear in the records. Although no ancient author establishes a direct link between the two groups, some scholars have postulated that the Allobroges may be identified as descendants of Gaesatae.