Thomas Madox (1666 – 13 January 1727) was a legal antiquary and historian, known for his publication and discussion of medieval records and charters; and in particular for his History of the Exchequer, tracing the administration and records of that branch of the state from the Norman Conquest to the time of Edward II. It became a standard work for the study of English medieval history. He held the office of historiographer royal from 1708 until his death.
Madox was born in 1666. He applied himself at an early age to the study of the common law, and was admitted to the Middle Temple, though he was never called to the bar. He became a sworn clerk in the Lord Treasurer's remembrance office (i.e. official archives), and afterwards joint clerk in the Augmentation Office, which administered the crown estates; first with Charles Batteley, who died in May 1722, and afterwards with John Batteley.
There he pursued his historical researches under the patronage of Lord Somers. He made his first appearance as an author with the publication of Formulare Anglicanum in 1702, concerning ancient charters, which Madox introduced with a learned dissertation on the subject. The principal materials for this work were obtained from the archives of the court of augmentations. It is "justly" (according to the Dictionary of National Biography) described by Bishop William Nicolson as "of unspeakable service to our students in law and antiquities". On the motion of Peter Le Neve, Madox was elected a member of the Society of Antiquaries in January 1708.