William Chaloner (1650s, or 1665–1699) was a serial counterfeit coiner and confidence trickster, who was imprisoned in Newgate Prison several times and eventually proven guilty of high treason by Sir Isaac Newton, Master of the Royal Mint. He was hanged on the gallows at Tyburn on 22 March 1699.He grew up in a poor family in Warwickshire, but through a career in counterfeiting and con artistry attained great wealth, including a house in Knightsbridge.