Sir Thomas Jenner (1637–1707) was an English barrister, baron of the exchequer and justice of the common pleas, closely associated with the Stuart kings Charles II and James II of England.
He was born at Mayfield, Sussex, eldest son of Thomas Jenner of that place, and Dorothy, his wife, daughter of Jeffrey Glyde of Dallington. He was educated at Tunbridge grammar school, under Nicholas Grey. In 1665 he became a pensioner of Queens' College, Cambridge, but left without taking a degree. He entered the Inner Temple in 1658, and was called to the bar in 1663, after which he practised chiefly in the court of exchequer.
In 1683 Charles II, having withdrawn the charter of the city of London, appointed a lord mayor, two sheriffs, and a recorder, who was Jenner. A few days earlier Jenner was knighted, and received an augmentation of arms. In the following January he was made king's sergeant. As king's sergeant and as recorder he took part in the state trials of the next two years, including those of Algernon Sidney and Henry Cornish. In the parliament of 1685 he represented the borough of Rye, until in 1686 be was raised to the bench as a Baron of the Exchequer. With the majority of the judges, Jenner gave judgment in favour of the king's claim to the dispensing power which was raised in the case of Sir Edward Hales.
In October 1687 Jenner was appointed one of the three royal commissioners to inquire into the appointment of a president of Magdalen College, Oxford; the other commissioners were Robert Wright and Thomas Cartwright. Jenner's diary of the proceedings survived in the library of Magdalen College. Cartwright sought to have him dismissed from the commission, finding him too moderate if outwardly overbearing to the fellows, and in the end Jenner voted against the expulsions.