William Wyndham, 3rd Bart of Orchard Windham, was born 1687 to Edward Wyndham (c1667-1695) and Catharine Leveson-Gower (1670-1704) and died 17 July 1740 of unspecified causes. He married Catherine Seymour (c1693-1731) 15 July 1708 . He married Maria Catherina Haeck de Jong (c1683-1779) 1 June 1734 .
|Offspring of William Wyndham and Catherine Seymour (c1693-1731)|
|Charles Wyndham, 2nd Earl of Egremont (1710-1763)||19 August 1710||21 August 1763||Alicia Maria Carpenter (c1726-1794)|
|Elizabeth Wyndham (bef1731-1769)||1731||5 December 1769||George Grenville (1712-1770)|
|Percy Wyndham, 1st Earl of Thomond (c1723-1774)|