Groslay (French pronunciation: [ɡʁolɛ] ⓘ) is a commune in the Val-d'Oise department in Île-de-France in northern France.

The nature of the soil was particularly favorable for wine growing, which was exploited here from antiquity until the late 19th century phylloxera epidemic.

Groslay hasn't been subjected to large scale urbanization in the 1960s and the 1970s unlike many of its neighbours.

The municipal park and the square in front of the town hall were completely renovated in 2007.

The commune is served at line 95.02 with the CIF (Montmorency-Charles de Gaulle International Airport).