Maria Janetta Beauclerk, Duchess of St Albans (c. 1779 – 17 January 1822), formerly Maria Janetta Nelthorpe, was the second wife of William Beauclerk, 8th Duke of St Albans, and the mother of the 9th Duke.
[1] Maria was the only daughter of John Nelthorpe and his wife, the former Mary Cracroft, of Little Grimsby Hall.
Maria married the future duke on 4 March 1799, at Little Grimsby, Lincolnshire, his first wife, Charlotte Thelwell, having died in October 1797, leaving no surviving children.
Beauclerk inherited the dukedom in 1816, as a result of the death, in infancy, of his nephew, Aubrey Beauclerk, 7th Duke of Saint Albans.
The couple had thirteen children: The duchess died in London, and was outlived by her husband.