The Dauphiné (UK: /ˈdoʊfɪneɪ, ˈdɔːf-/ DOH-fin-ay, DAW-, US: /ˌdoʊfiːˈneɪ/ DOH-fee-NAY, French: [dofine]; Occitan: Daufinat or Dalfinat; Arpitan: Dôfenât or Darfenât), traditionally known in English as Dauphiny, is a former province in southeastern France during the Ancien régime, whose area roughly corresponded to that of the present-day departments of Isère, Drôme and Hautes-Alpes. The Dauphiné was originally the Dauphiné of Viennois.

In the 12th century, the local ruler Count Guigues IV of Albon (c. 1095–1142) bore a dolphin on his coat of arms and was nicknamed le Dauphin (French for 'dolphin'). His descendants changed their title from Count of Albon to Dauphin of Viennois. The state took the name of Dauphiné. It became a state of the Holy Roman Empire in the 11th century.

In 1349, the Dauphiné was transferred from the last non-royal Dauphin (who had great debts and no direct heir) to the future king of France, Charles V, through the purchase of lands. The terms of the transfer stipulated that the heir apparent of France would henceforth be called le Dauphin and included significant autonomy and tax exemption for the Dauphiné region, most of which it retained only until 1457, though it remained a province until the French Revolution. Dauphin of France remained the title of the eldest son of a king of France and the heir apparent to the French crown until 1830.

The historical capital is Grenoble and the other main towns are Vienne, Valence, Montélimar, Gap and Romans-sur-Isère. The demonym for its inhabitants is Dauphinois.

Under the Ancien Régime, the province was bordered in the North by the River Rhône which separated the Dauphiné from the Bresse ("Brêsse") and Bugey ("Bugê"). To the east it bordered the Savoy and Piedmont, and to the south the Comtat Venaissin and Provence. The western border was marked by the Rhône to the south of Lyon. The Dauphiné extended up to what is now the centre of Lyon. It was divided into the "High Dauphiné" and "Low Dauphiné". The first covered:

The second included:

The province also included the current Italian Dauphiné, which belonged to the Republic of the Escartons until 1713, when it was ceded to the Duchy of Savoy by the Treaty of Utrecht. The Vivaro-Alpine dialect was still spoken there until the 20th century:

The province offers a range of terrain, from the alpine summits of the High-Dauphiné (the Barre des Ecrins is 4,102 meters at its highest point), the Prealps (Vercors and Chartreuse), and the plains of the Drôme, which resemble the landscapes of Provence.