Mézières-sur-Couesnon (French pronunciation: [mezjɛʁ syʁ kwenɔ̃], literally Mézières on Couesnon; Breton: Magoerioù-ar-C'houenon; Gallo: Maézierr) is a commune in the Ille-et-Vilaine department in Brittany in northwestern France.

Mézières-sur-Couesnon is located 30 km (19 mi) northeast of Rennes and 42 km (26 mi) south of Mont Saint-Michel.

The bordering communes are Saint-Ouen-des-Alleux, Saint-Marc-sur-Couesnon, Saint-Jean-sur-Couesnon, Saint-Aubin-du-Cormier, Gahard, and Vieux-Vy-sur-Couesnon.

Inhabitants of Mézières-sur-Couesnon are called Mézièrais in French.

This Ille-et-Vilaine geographical article is a stub.