John Ker, 5th Earl of Roxburghe

John Ker, 1st Duke of Roxburghe, KG, PC, FRS (30 April 1680–27 February 1741) was the second son of Robert Ker, 3rd Earl of Roxburghe, and Margaret Hay, daughter of John Hay, 1st Marquess of Tweeddale. He was younger brother to Robert Ker, 4th Earl of Roxburghe.

John became 5th Earl of Roxburghe on the death of his brother Robert in 1696. 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. This was the last creation in the Scottish peerage. On 28 May 1707, he was admitted a FRS.

The duke was a representative peer for Scotland in four parliaments. George I made him a privy councillor and Keeper of the Privy Seal of Scotland, and he was loyal to the king during the Jacobite rising in 1715. 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. In Apr 1727 he was one of the six pall-bearers of Sir Isaac Newton's coffin at Westminster Abbey. He was one of the original governors of the Foundling Hospital, a charity created by royal charter on 17 October 1739.