Mervyn Tuchet, 2nd Earl of Castlehaven (1593 – 14 May 1631; also spelled Mervin, Touchet), was an English nobleman who was convicted of rape and sodomy and subsequently executed. He is the only member of parliament to be executed for a non-political crime. A son of George Tuchet, 1st Earl of Castlehaven and 11th Baron Audley, by his wife, Lucy Mervyn, he was known by the courtesy title of Lord Audley during his father's lifetime, so is sometimes referred to as Mervyn Audley.