John Sholto Douglas, 9th Marquess of Queensberry (20 July 1844 – 31 January 1900) was a Scottish nobleman, remembered for lending his name and patronage to the "Marquess of Queensberry Rules" that formed the basis of modern boxing and for his role in the downfall of author and playwright Oscar Wilde.
Douglas was born in Florence, Italy, the eldest son of Scottish Conservative Party politician Archibald, Viscount Drumlanrig and Caroline Margaret Clayton. He was briefly styled Viscount Drumlanrig following his father's succession in 1856, and on his father's death in 1858 he inherited the Marquessate of Queensberry. The 9th Marquess was educated in the training ships Illustrious and Britannia at Portsmouth, and served in the Royal Navy until resigning in 1864. He was Lieutenant-Colonel commanding the 1st Dumfriesshire Rifle Volunteers from 1869 to 1871.
In 1864 he entered Magdalene College, Cambridge, which he left two years later without taking a degree. He was more distinguished in sport, playing college cricket as well as running, hunting and steeplechasing.
Marquess of Queensberry is a title in the Peerage of Scotland. The title has been held since its creation in 1682 by a member of the Douglas family. The Marquesses also held the title of Duke of Queensberry from 1684 to 1810, when it was inherited by the Duke of Buccleuch.
The feudal barony of Drumlanrig was held by William Douglas, illegitimate son of James Douglas, 2nd Earl of Douglas, some time before 1427, when he died. His descendant William Douglas, 9th of Drumlanrig, was created the 1st Earl of Queensberry in 1633.
The subsidiary titles of Lord Queensberry are: Earl of Queensberry (created 1633), Viscount Drumlanrig (1628) and Lord Douglas of Hawick and Tibbers (1628), all in the peerage of Scotland. He is also a Scottish baronet, styled "of Kelhead", created 26 February 1668, so the 6th Marquess was the 5th Baronet. The courtesy title used by Lord Queensberry's eldest son and heir is Viscount Drumlanrig. There is no special courtesy title for Lord Drumlanrig's eldest son and heir.