Thomas Thynn, 1st Viscount Weymouth (c. 1640–1714), was an English nobleman and politician. He was born into a prominent family and became a member of the House of Commons, representing Wiltshire. In 1682, he was elevated to the peerage as the Viscount Weymouth, which granted him a higher social status and greater influence. As a landowner, Thynn managed extensive estates and was involved in local governance. He was known for his contributions to the development of Longleat House, a grand stately home in Wiltshire, which remains a significant historical site today. His legacy includes both his political career and his impact on English heritage.