James Compton, 3rd Earl of Northampton FRS (19 August 1622 – 15 December 1681), known as Lord Compton from 1630 to 1643, was an English peer, soldier, and politician.
Northampton was the eldest son of Spencer Compton, 2nd Earl of Northampton, and Mary Beaumont. He sat as Member of Parliament for Warwickshire from 1640 to 1642. The following year his father was killed at the Battle of Hopton Heath and he succeeded in the earldom. Like his father, Northampton was an ardent Royalist and during the Civil War notably commanded his regiment of cavalry at the First Battle of Newbury in 1643. He was also Lord Lieutenant of Warwickshire between 1660 and 1681 and Constable of the Tower of London from 1675 to 1679.
Lord Northampton married, firstly, Isabella, daughter of Richard Sackville, 3rd Earl of Dorset, in 1647. He married, secondly, Mary, daughter of Baptist Noel, 3rd Viscount Campden. His third son from his second marriage, Spencer, became a prominent politician and served as Prime Minister of Great Britain from 1742 to 1743. In 1730 he was created Earl of Wilmington. Lord Northampton died in December 1681, aged 59, and was succeeded in his titles by his eldest son George.