Thomas Thynne, 2nd Viscount Weymouth (21 May 1710 – 1751) of Longleat House in Wiltshire was an English peer, descended from Sir John Thynne (c.1515-1580) builder of Longleat.
He was born on 21 May 1710, the son of Thomas Thynne (d.1710) by his wife Lady Mary Villiers.
On 28 July 1714, aged four, on the death of his great uncle Thomas Thynne, 1st Viscount Weymouth, he inherited Longleat House and its great estates and succeeded to the baronetcy of Thynne, of Kempsford, Gloucestershire, and (by special remainder) to the titles of Baron Thynne of Warminster, Wiltshire, and Viscount Weymouth, of Dorset.
[1] He also inherited land at Buckland, Gloucestershire on the death of his uncle James Thynne in 1709.
Shortly after his Hyde Park appointment, he began the construction of the Serpentine Lakes at Longleat, apparently in imitation of Hyde Park's Serpentine.