Thomas Thynne, 2nd Marquess of Bath KG, styled Viscount Weymouth from 1789 until 1796, was a British peer.

Thomas Thynne, 1st Marquess of Bath, KG, PC, of Longleat in Wiltshire, was a British politician who held office under King George III. He served as Southern Secretary, Northern Secretary and Lord Lieutenant of Ireland. Between 1751 and 1789, he was known as the 3rd Viscount Weymouth. He is possibly best known for his role in the Falklands Crisis of 1770.