Aquitaine (; ; ; ; ), archaic Guyenne/Guienne (Occitan: Guiana) was a traditional region of France, and was a administrative region of France until 1 January 2016. It is now part of the new region Aquitaine-Limousin-Poitou-Charentes. It is situated in the south-western part of Metropolitan France, along the Atlantic Ocean and the Pyrenees mountain range on the border with Spain. It is composed of the five departments of Dordogne, Lot-et-Garonne, Pyrénées-Atlantiques, Landes and Gironde. In the Middle Ages Aquitaine was a kingdom and a duchy, whose boundaries fluctuated considerably.

Gallia Aquitania (), also known as Aquitaine or Aquitaine Gaul, was a province of the Roman Empire. It lies in present-day southwest France, where it gives its name to the modern region of Aquitaine. It was bordered by the provinces of Gallia Lugdunensis, Gallia Narbonensis, and Hispania Tarraconensis.