Jouy-en-Josas (French pronunciation: [ʒwi ɑ̃ ʒozas] ⓘ) is a commune in the Yvelines department in the Île-de-France region in Northern France.

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.

Stimulated by the presence of monks from the abbey of Saint-Germain-des-Prés in Paris, Jouy grew rapidly, but the population was progressively annihilated in the fourteenth century by a number of wars and epidemics.

In 1759, Christophe-Philippe Oberkampf, an entrepreneur of German origins, moved to Jouy-en-Josas and started a factory there, which produced toile de Jouy, a cotton fabric printed with isolated engraved vignettes of historical figures or landscapes, usually printed in red or green on white cotton.

The Cartier Foundation for Contemporary Art settled in Jouy-en-Josas for a short time, before moving to the Boulevard Raspail in Paris.