Saint-Maurice-sur-Adour (; literally "Saint-Maurice on Adour"; ) is a commune in the Landes department in Nouvelle-Aquitaine in southwestern France.
The commune of Saint-Maurice-sur-Adour is located south of Mont-de-Marsan. It originated as a bastide (fortified town) built in the 13th century by Edward II of England. The village is rustic, and contains a 16th-century church and the Château de Saint Maurice.