John Forest was a 15th-century English Franciscan friar and provincial superior of the Observant Friars. Born in Oxford, he eventually served as the confessor to Catherine of Aragon, the first wife of Henry VIII. Because he refused to recognize the king's supremacy over the church, he faced significant persecution during the English Reformation. After being imprisoned and writing a defense of papal authority, he was ultimately executed in London for heresy and high treason.