John Ker, 1st Duke of Roxburghe, KG, PC, FRS (30 April 1680[1] – 27 February 1741) was a Scottish nobleman.

William Ker, who fought on the Continent under the Duke of Marlborough and was present at the Battle of Sheriffmuir.

He served as Groom of the Bedchamber to the Prince of Wales in 1714, and was a Member of Parliament for Berwick and Dysart Burghs.

In 1704, he was made a Secretary of State of Scotland, and he helped to bring about the union with England, being created Duke of Roxburghe in 1707 for his services in this connection.

He served as Secretary of State for Scotland in the British Parliament from 1716 to 1725, but he opposed the malt tax, and in 1725 Sir Robert Walpole procured his dismissal from office.