Jouy-en-Josas is four kilometres to the south-east of Versailles, and 19r km to the south-west of Paris, in the middle of the valley of the Bièvre river.
The communes that surround Jouy-en-Josas are Vélizy-Villacoublay, to the north-east, Bièvres to the east, Saclay to the south, Toussus-le-Noble to the extreme south-west, Les Loges-en-Josas to the west, Buc to the north-west and Versailles to the north-north-west.