William Lowther JP DL (14 December 1821 – 23 January 1912) was a British diplomat and Conservative politician who sat in the House of Commons from 1868 to 1892.

[1] His paternal grandparents were William Lowther, 1st Earl of Lonsdale and the former Lady Augusta Fane (eldest daughter of John Fane, 9th Earl of Westmorland and, his first wife, Augusta Bertie, a granddaughter of Robert Bertie, 1st Duke of Ancaster and Kesteven).

His maternal grandparents were Philip Sherard, 5th Earl of Harborough and the former Eleanor Monckton (second daughter and co-heiress of Col. Hon.

He was Secretary of the Embassy at Berlin from 1861 to 1867 and finally Minister to Argentina at Buenos Aires from 1867 to 1868.

In 1873, he was granted the style and precedence of the younger son of an Earl by Royal Warrant.