Montigny-le-Bretonneux is a commune situated in the Yvelines department within the Île-de-France region of north-central France. It is located approximately 24.5 kilometres from the centre of Paris, positioned in the south-western suburbs.
The commune serves as the central and most populated municipality of the "new town" known as Saint-Quentin-en-Yvelines. Its location within this urban development area characterizes its role as a significant residential and administrative hub in the Parisian outskirts.