The Agout is a long river in south-western France, left tributary of the Tarn River. Its source is in the southern Massif Central, in the Parc naturel régional du Haut-Languedoc. It flows generally west through the following départements and towns:
- Hérault: La Salvetat-sur-Agout
- Tarn: Brassac, Castres, Lavaur, Saint-Sulpice
The Agout flows into the Tarn River in Saint-Sulpice.
Among its tributaries are the Dadou, the Gijou and the Thoré.