Francis II of Brittany (in Breton Frañsez II, in French François II) (23 June 1433 – 9 September 1488) was Duke of Brittany from 1458 to his death.
He was the grandson of John IV, Duke of Brittany.
A recurring theme in Francis' life would be his quest to maintain the quasi-independence of Brittany from France.
As such, his reign was characterized by conflicts with King Louis XI of France and with his daughter, Anne of France, who served as regent during the minority of her brother, King 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".