Francis II of Brittany (in Breton Frañsez II, in French François II) (June 23, 1433 – September 9, 1488) is Duke of Brittany from 1458 to his death.

He is the son of Richard of Brittany and the grandson of Duke John V. A recurring theme in Francis' life is his quest to maintain the independence of Brittany from France.

As such, his reign is characterized by conflicts with King Louis XI of France and with his daughter, Anne of France, who servez as regent during the minority of her brother, Charles VIII.

The armed and unarmed conflicts between 1484-1488 have been called the Mad War (la Guerre Folle) and also the War of the Public Weal.