Joan of Navarre, also known as Joanna (c. 1370 – 10 June 1437) was a Duchess consort of Brittany and a Queen consort of England. She was the regent of Brittany from 1399 until 1403 during the minority of her son. She was a daughter of King Charles II of Navarre and Joan of France. She was the Duchess consort of Brittany through marriage with John IV, Duke of Brittany and later the Queen consort of England through marriage with King Henry IV of England.