Arnold Oldsworth (born c. 1561) was an English lawyer and politician who sat in the House of Commons at various times between 1593 and 1611.
He was educated under Alexander Nowell, dean of St. Paul's and matriculated at Magdalen Hall, Oxford under date 7 July 1575, aged 17.
He was keeper of the Hanaper in Chancery, and Receiver of the Fines in the King's Bench.
He was of Bradley, Gloucestershire and lived in St. Martin's Lane, London.
He and his wife had a grant of lands in Brenchley and elsewhere in Kent on 29 March 1616.