Montigny-lès-Cormeilles (French pronunciation: [mɔ̃tiɲi lɛ kɔʁmɛj] ⓘ, literally Montigny near Cormeilles) is a commune in Val d'Oise, in the northwestern suburbs of Paris, France.

It is located 19.0 km (11.8 mi) from the center of Paris.

Montigny-lès-Cormeilles is served by Montigny–Beauchamp station on Paris RER line C and on the Transilien Paris-Nord suburban rail line.

Montigny-lès-Cormeilles is also served by La Frette–Montigny station on the Transilien Paris-Saint-Lazare suburban rail line.

This station, although administratively located on the territory of the neighboring commune of La Frette-sur-Seine, lies in fact very near the town center of Montigny-lès-Cormeilles.