Sir Henry Pollexfen (1632 – 15 June 1691) was Lord Chief Justice of the Common Pleas.
He was the son of Andrew Pollexfen and his wife Joan, and the brother of John Pollexfen, the British political economist. He entered Inner Temple in 1652, was called to the bar in 1658 and by 1662 he was pleading before the high courts at Westminster Hall. In 1674 he became a bencher at Inner Temple, and was the leading practitioner on the western circuit, frequently pleading at the King's Bench. In 1676 he defended on a Quo warranto charge, which he lost. He frequently acted as counsel in various politically charged cases, and regularly lost; clients included the lords involved in the Popish Plot, the Earl of Danby and as one of many counsel for Edward Fitzharris, Stephen College and Algernon Sidney, all of whom were later executed. Along with Sir George Treby and Sir Francis Winnington he defended London on a second Quo warranto charge in 1683, arguing that Corporations could not be charged for the wrongdoing of individuals. He lost, and in 1684 was asked to take a similar case for Berwick-upon-Tweed, this time advising surrender.
In 1688 he was made a justice, and advised the House of Lords on the legality of Quo warranto seizures. After William III arrived in 1688 he was a close advisor, and helped persuade him to declare himself King, arguing that the throne was vacant due to James fleeing, saying James ‘went away because the terror of his own conscience frighted him and he durst stay no longer’. William did not make himself King according to Pollexfen's advice, but in reward for his services Pollexfen was knighted and made Attorney General for England and Wales in March, and appointed Chief Justice of the Common Pleas on 6 May 1689. In late 1689 he was elected Member of Parliament representing Exeter at the 1689 Convention Parliament, where William was officially offered the crown. After serving as Chief Justice for two years Pollexfen died of a burst blood vessel at his home in Lincoln's Inn Fields on 15 June 1691.