David Wemyss, 4th Earl of Wemyss (29 April 1678 – 15 March 1720), was a Scottish peer and Member of Parliament who served as Lord High Admiral of Scotland from 1706 to 1714.
His elder sister was Lady Anne Wemyss (d. 1702), who married David Melville, 3rd Earl of Leven, and his younger sister was Lady Margaret Wemyss, who married David Carnegie, 4th Earl of Northesk.
Lord Wemyss entered parliament as a peer on 28 June 1705, and was the same year sworn of the privy council.
The Earl of Wemyss was one of four non-medicals who was granted an Honorary Fellowship in the first 25 years of the Royal College of Physician's life.
His third marriage as in July 1716, to Elizabeth St. Clair (d. 1721), the daughter of Henry, Lord Sinclair.