John Douglas, 7th Marquess of Queensberry (1779 – 19 December 1856), styled Lord John Douglas from May to December 1837, was a Scottish Whig politician.
Queensberry was the son of Sir William Douglas, 4th Baronet (died 16 May 1783), and his wife Grace (née Johnstone) who died 25 March 1836, and succeeded his elder brother, Charles (1777–1837), in the marquessate in December 1837. The same year he was appointed a Lord-in-Waiting (government whip in the House of Lords) in the Whig administration of Lord Melbourne, a position he held until the government fell in 1841. Between 1837 and 1850 he also served as Lord-Lieutenant of Dumfriesshire.
Lord Queensberry married Sarah (died 13 November 1864), daughter of James Sholto Douglas, on 16 July 1817.