Ridgeway Pitt, 3rd Earl of Londonderry

Ridgeway Pitt, 3rd Earl of Londonderry (1722 – 1765) was a British politician and peer.

He was the younger son of Thomas Pitt, 1st Earl of Londonderry. His older brother, Thomas, died in a riding accident in 1734, at which point Londonderry succeeded to his titles. In 1740 he was admitted to St John's College, Cambridge. He took his seat in the Irish House of Lords on 29 October 1743. As his title was in the Peerage of Ireland, he was not barred from election to the House of Commons of Great Britain. As such, he sat as the Member of Parliament for the rotten borough of Camelford in Cornwall between 1747 and 1754.

Londonderry never married. Upon his death, his titles became extinct.