The Romanche (French pronunciation: [ʁɔmɑ̃ʃ] (listen)) is a 78.3-kilometre (48.7 mi) long mountain river in southeastern France. It is a right tributary of the Drac, which is itself a tributary of the Isère. Its drainage basin is 1,221 km² (471 sq mi). Its source is in the northern part of the Massif des Écrins, Dauphiné Alps. It flows into the Drac in Champ-sur-Drac, south of Grenoble. The road from Grenoble to Briançon over the Col du Lautaret runs through the Romanche valley. There are several mountain and ski resorts in the valley, including Alpe d'Huez, La Grave and Les Deux Alpes.

The Romanche flows through the following departments and towns:

• Hautes-Alpes: La Grave
• Isère: Mont-de-Lans, Le Bourg-d'Oisans, Livet-et-Gavet, Vizille