John Houghton was a Carthusian priest and hermit living in 16th-century England. Born in Essex around 1486, he served in various leadership roles within his order, including prior of the London Charterhouse and Provincial Visitor. He is recognized as the first martyr to die following the implementation of the Act of Supremacy under King Henry VIII. Because of his refusal to acknowledge the King as the supreme head of the Church, he was arrested and eventually executed at Tyburn in 1535.