Thomas Thynn, 3rd Viscount Weymouth (1797–1837), was a British nobleman known for his role in the House of Lords. He inherited the title from his father, Thomas Thynn, 2nd Viscount Weymouth, and was involved in various social and political activities during his lifetime. He was also a prominent landowner, managing estates in Weymouth and Marlborough. His contributions to society included supporting local initiatives and participating in the cultural life of his time. Thomas Thynn's legacy continued through his descendants, maintaining the family's influence in British aristocracy.