Sir William Wyndham, 3rd Baronet

The Right Honourable Sir William Wyndham Bt
Sir William Wyndham, 1713 portrait by Jonathon Richardson, National Portrait Gallery, London
Chancellor of the Exchequer
In office 1713–1714
Preceded by	Sir Robert Benson
Succeeded by	Sir Richard Onslow
Secretary at War
In office 1712–1713
Preceded by	George Granville
Succeeded by	Francis Gwyn
Personal details
Alma mater	Christ Church, Oxford

Sir William Wyndham, 3rd Baronet (c. 1688 – 17 June 1740), of Orchard Wyndham in Somerset, was an English Tory statesman, who served as Secretary at War in 1712 and Chancellor of the Exchequer in 1713 during the reign of the last Stuart monarch, Queen Anne (1702–1714). He was a Jacobite leader firmly opposed to the Hanoverian succession and was leader of the Tory opposition in the House of Commons during the reign of King George I (1714–1727) and during the early years of King George II (1727–1760).

His first wife was Lady Catherine Seymour, the younger of the two daughters of Charles Seymour, 6th Duke of Somerset (died 1748), and in her children by Wyndham, heiress to half of the vast estates, including Petworth House in Sussex and Egremont Castle in Cumberland, formerly held by the extinct Percy family, Earls of Northumberland. As a result of this complex inheritance his eldest son became the 2nd Earl of Egremont. Both his sons became earls and his daughter Elizabeth Wyndham was both the wife and mother of Prime Ministers, namely George Grenville and William Wyndham Grenville respectively.

He built the pier at Watchet harbour, near Orchard Wyndham.

He was the son and heir of Sir Edward Wyndham, 2nd Baronet (c. 1667 – 1695) of Orchard Wyndham, three times Member of Parliament for Ilchester, Somerset, by his wife Katherine Leveson-Gower, eldest daughter of Sir William Leveson-Gower, 4th Baronet.