Massy is served by two interchange stations on Paris RER line B and RER line C: Massy - Verrières and Massy - Palaiseau.
There is also a TGV station, called Massy TGV, which is adjacent to Massy - Palaiseau station and is one of only three specially-built TGV stations in the suburbs of Paris (the two others are at Disneyland Resort Paris and at Charles de Gaulle Airport).