Sir William Bucknall (25 July 1633 – 1676), of Oxhey, Hertfordshire, was an English merchant, excise farmer and politician who sat in the House of Commons from 1670 to 1676. Bucknall was the brother of Ralph Bucknall. In 1752, he became a Freeman of the Salters’ Company and acquired interests in water supply and shipping. He married Sarah Chitts, daughter of Thomas Chitts, Woodmonger, of London in 1753. Bucknall died on 26 October 1676, and was buried at Oxhey. He left six surviving sons and three daughters. His son was elected for Middlesex in 1696. His daughter married John Ward.