William FitzWilliam, 1st Viscount FitzWilliam (1748–1833), was an English politician and nobleman. He served as a member of the House of Commons and held various political positions, including Lord Lieutenant of the West Riding of Yorkshire. FitzWilliam was known for his contributions to the development of the region and his involvement in local governance. In 1797, he was elevated to the peerage as Viscount FitzWilliam, which granted him a higher status in the British aristocracy. He was also a significant landowner, with extensive estates that included Wentworth Woodhouse, one of the largest country houses in England.