Denzil Onslow of Pyrford (c.1642 – 27 June 1721) was a British Whig politician who sat in the English and British House of Commons between 1679 and 1721. Through advantageous marriages, he obtained a country estate and became prominent in Surrey politics of the Hanoverian era, although his great nephew Arthur Onslow, as Speaker, judged that Denzil knew "no more of the business [of the House of Commons] than one who had been of the standing of a session".