Cloyes-sur-le-Loir (, literally Cloyes on the Loir) is a former commune on the River Loir, a few kilometres south of the town of Châteaudun in the department of Eure-et-Loir in northern France. On 1 January 2017, it was merged into the new commune Cloyes-les-Trois-Rivières.
It was the home of Stephen of Cloyes, a leader of the Children's Crusade. Mezzo-soprano Juliette Borghèse was born in the town.