David Harrington Angus Douglas, 12th Marquess of Queensberry (born 19 December 1929, London) is an Anglo-Scottish aristocrat and noted pottery designer.
Queensberry is the elder son of the 11th Marquess, and his only son by his second wife, artist Cathleen Sabine Mann (married 1926 – divorced 1946). His maternal grandparents were interior decorator Dolly Mann (née Florence Sabine-Pasley) and artist Harrington Mann. He succeeded his father in 1954.
Educated at Eton College, he served in the Royal Horse Guards. In the 1950s he worked in the pottery industry. He was Professor of Ceramics at the Royal College of Art from 1959-83. He belongs to the Crafts Council, was President of the Design and Industries Association from 1976–78, is a Fellow of the Chartered Society of Designers (and recipient of the Minerva Medal, the Society's highest award), and was Senior Fellow of the Royal College of Art from 1990, and Professor of Ceramics there.
As a hereditary peer, he spoke in the House of Lords in the 1960s. Under the Peerage Act 1963 which came into effect in August that year, all Scottish peers were given seats in the House of Lords as of right. This right was lost under the House of Lords Act 1999 which provided that "[n]o-one shall be a member of the House of Lords by virtue of a hereditary peerage."
His great-grandfather the 9th Marquess of Queensberry had been instrumental in the imprisonment for homosexuality of playwright Oscar Wilde; the 12th Marquess spoke in the House of Lords in favour of the decriminalisation of homosexuality in the debates leading to the Sexual Offences Act 1967. He said in 2016 that he had been delighted to associate his family with a liberalising measure. "The Queensberry name had become so associated with the way Oscar Wilde was pilloried in 1895."