Saint-Marcellin is a soft French cheese made from cow's milk.

Named after the small town of Saint-Marcellin (Isère), it is produced in a geographical area corresponding to part of the former Dauphiné province (now included in the Rhône-Alpes région).

[1]: 162  It is generally small in size, weighing about 80 grams (50% fat), with a mottled creamy-white exterior.

[1]: 162  The degree of runniness increases with age as the exterior gains blue, then yellow, hues within two to three weeks after production.

[1]: 162 It is similar in texture and taste to Saint-Félicien, a larger cheese produced in a different part of the Rhône-Alpes région.