Lord Francis Douglas Marquess of Queensberry; a younger brother, Lord Archibald Edward Douglas (1850–1938), who became a clergyman; and a younger brother and sister, the twins Lord James Douglas (d. 1891) and Lady Florence Douglas (1855–1905), who married Sir Alexander Beaumont Churchill Dixie, 11th Baronet. He was an uncle of Oscar Wilde's lover Lord Alfred Douglas, and a younger brother of John Douglas, 9th Marquess of Queensberry. In 1858, Douglas's father, Lord Queensberry, died in what was reported as a shooting accident, but his death was widely believed to have been suicide. In 1862, his mother, Lady Queensberry, converted to Roman Catholicism and
Lord Alfred Douglas and threatening to beat people with a horsewhip. Alfred sent his father a postcard stating "I detest you" and making it clear that he would take Wilde's side in a fight between him and the Marquess, "with a loaded revolver". In answer Queensberry wrote to Alfred (whom he addressed as "You miserable creature") that he had divorced Alfred's mother in order not to "run the risk of bringing more creatures into the world like yourself" and that, when Alfred was a baby, "I cried over you the bitterest tears a man ever shed, that I had brought such a creature