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
James Douglas, 1st Lord Mordington child and daughter of Laurence Oliphant, 5th Lord Oliphant. This lady claimed the peerage of Oliphant, but in the Court of Session in 1633, it was determined, in the presence of King Charles I, in favour of the heir male. The king, however, decided to create her husband a peer with the title of Lord Mordington, with the precedency of Oliphant (1458). They had: James Douglas, 1st Lord Mordington Sir James Douglas, 1st Lord Mordington (died 11 February 1656) was the second son of William Douglas, 10th Earl of Angus by his spouse Elizabeth, daughter of Laurence Oliphant, 4th Lord