Poissy (French: [pwasi] ⓘ) is a commune in the Yvelines department in the Île-de-France region in north-central France.

The area is known for hosting the Automobiles Gregoire successively, Matford, Ford SAF, Simca, Chrysler, Talbot factories and now hosts one of France's largest Peugeot factories.

The city is limited to the east by the forest of Saint-Germain-en-Laye and to the west by the Seine.

Technoparc is a Business Park created in 1990, with the intention to facilitate the economic diversification of the city.

It occupies about 66 acres on the northeast of Stellantis plant, bordering the neighbouring commune Achères.