Joan of France or Joan of Valois (French: Jeanne; 24 January 1391 – 27 September 1433) was Duchess of Brittany by marriage to John V. She was a daughter of Charles VI of France and Isabeau of Bavaria.

As duchess, Joan is perhaps most known for her role during the conflict between John V and the Counts of Penthièvre.

Despite the military loss and the diplomatic treaty, the Counts of Penthièvre had not renounced their ducal claims to Brittany and continued to pursue them.

The Counts of Penthiève then spread rumours of his death, and moved him to a new prison each day.

Joan ended the conflict by seizing the dowager countess of Penthièvre, Margaret of Clisson, and forcing her to have the duke freed.