Sir William Owen, 4th Baronet (1697?–1781), of Orielton, Pembrokeshire, was a Welsh politician who sat in the House of Commons for 52 years from 1722 to 1774. Owen was the eldest son of Sir Arthur Owen, 3rd Baronet, and his wife Emma Williams, daughter of Sir William Williams, 1st Baronet. He matriculated at New College, Oxford, on 16 June 1713, aged 16. He married Elizabeth Lloyd, daughter of Thomas Lloyd of Grove, Pembrokeshire, on 12 December 1725. He married as his second wife his cousin Anne Williams, daughter of John Williams of Chester, on 26 July 1728.