Réserve Naturelle Régionale du Massif de Saint-Barthélemy (RNR309) is a regional nature reserve in the Occitanie region of France. Classified in 2015, it covers an area of 460 hectares. It is located in the Saint-Barthélemy massif.

Visible from Toulouse to Carcassonne, via the Montagne Noire and the high peaks of the Couserans, the duo of the Soularac and Saint-Barthélemy peaks is the emblematic viewpoint of the Cathar Pyrenees. Well-known to hikers, it offers a unique panorama of the Pyrenean chain, from the Mediterranean to the 3000m peaks of the central Pyrenees.