John Pym (1584 – 8 December 1643) was an English parliamentarian, leader of the Long Parliament and a prominent critic of Kings James I and then Charles I. He was one of the Five Members whose attempted arrest by King Charles I in the House of Commons of England in 1642 sparked the Civil War. In addition to this Pym went ahead and started to accuse William Laud (the king's adviser) of trying to convert England back to Catholicism.
Pym was born in Brymore, Cannington, Somerset, into minor nobility. His father died when he was very young and his mother remarried, to Sir Anthony Rous. Pym was educated in law at Broadgates Hall (now Pembroke College, Oxford) in 1599 and went on to the Middle Temple in 1602. In May 1614, he married Anne Hooke of Bramshott in Hampshire, aunt of Robert Hooke and daughter of John Hooke and Anthony Rous's sister Barbara, who bore five of his children. This marriage established Pym as a member of the Rous circle, which in turn influenced the development of his strong Puritanism and fierce opposition to Catholicism and Arminianism.
He entered politics through the influence of the Earl of Bedford, working for the Exchequer in Wiltshire before entering Parliament for Calne, Wiltshire in 1614. Despite his Puritanism he gained a good reputation in Parliament, although he was relentless in his campaigning against Roman Catholics. After the dissolution of Parliament in 1621 he was one of those placed under house-arrest in January 1622. In 1624 he changed his seat, representing , Devon, for the rest of his career.