The Chassezac (French pronunciation: [ʃaszak]; Occitan: Chassesac) is an 84.6 km (52.6 mi) long river in the Lozère, Gard and Ardèche departments in southern France. It is a right tributary of the Ardèche. Its source is in the commune of Saint-Frézal-d'Albuges, 2.8 km (1.7 mi) northeast of Les Chazeaux, the main hamlet in the commune. It flows generally southeast and flows into the Ardèche at Saint-Alban-Auriolles, 1.8 km (1.1 mi) east of the village itself.

The following list is ordered from source to mouth :

• Lozère: Saint-Frézal-d'Albuges, Belvezet, Chasseradès, La Bastide-Puylaurent, Prévenchères, Pied-de-Borne
• Ardèche: Sainte-Marguerite-Lafigère,
• Gard: Malons-et-Elze
• Ardèche: Malarce-sur-la-Thines, Gravières, Les Salelles, Chambonas, Les Assions, Les Vans, Berrias-et-Casteljau, Chandolas, Beaulieu, Grospierres, Sampzon, Saint-Alban-Auriolles,