The Parisii are a Celtic Iron Age people that live on the banks of the river Seine (in Latin, Sequana) in Gaul from the middle of the third century BCE until the Roman era.

With the Suessiones, the Parisii participate in the general rising of Vercingetorix against Julius Caesar in 52 BCE.Their chief city (oppidum) is on the site of Lutetia, which later becomes an important city in the Roman province of Gallia Lugdunensis and ultimately the modern city of Paris.

(The name Paris is derived from Parisii).Barry Cunliffe in Iron Age Communities in Britain (1974) p. 45, distinguishes the Parisii as those in the Nanterre-Paris region, and the Parisi as those who moved to Britain, based on Ptolemy's descriptions.