Coordinates: 46°57′33″N 3°04′46″E / 46.95917°N 3.07944°E / 46.95917; 3.07944

The Allier (Occitan: Alèir) is a river in central France, left tributary of the Loire River. It flows through several regions.

The Allier department is named after this river. In Ancient Rome, the river was named Elaver.