Other Lewis Windsor, 4th Earl of Plymouth (12 May 1731 – 21 April 1771) was a British peer, styled Lord Windsor until 1732.
He succeeded his father as Earl of Plymouth at the age of one, and was educated at Eton and The Queen's College, Oxford. In March 1750, he was appointed Constable of Flint Castle, Comptroller of the records in the counties of Chester and Flint, and Comptroller of the Pleas, Fine and Amerciaments in county Caernarvon. He obtained his Master of Arts in July.
In 1753, he was appointed Custos Rotulorum of Flintshire, and in 1754, Lord Lieutenant of Glamorgan. He was also made a deputy lieutenant of Worcestershire in 1757. He married Catherine, eldest daughter of Thomas Archer, 1st Baron Archer, on 11 August 1750.