Douglas Brooke Wheelton Sladen (5 February 1856, London-12 February 1947, Hove) was an English author and academic.

Educated at Temple Grove School, East Sheen,^[1] Cheltenham College, and Trinity College, Oxford, in 1879 Sladen migrated to Australia, where he became the first professor of history in the new University of Sydney.^[2] Subsequently he traveled much and settled in London as a writer. Poems by Margaret Thomas were included in a work in the 1880s.

His work includes:

• Frithjof and Ingebjorg (1882)
• Poetry of Exiles (1883)
• In Cornwall and Across the Sea (1885)
• Edward the Black Prince (1886), an epic drama
• The Spanish Armada (1888)
• The Japs at Home (1892)
• A Japanese Marriage (1895)
• A Sicilian Marriage (1905)
• Queer Things About Sicily with Norma Lorimer (1905)
• Carthage and Tunis: The Old and New Gates of the Orient (1906)
• Egypt and the English (1908)
• Queer Things About Egypt (1911)
• The Unholy Estate (1912)
• Twenty Years of my Life (1913)
• Queer Things about Japan^[3] (1913)
• The Real "Truth about Germany" (1914)
• His German Wife (1915)
• Fair Inez: A Romance of Australia (1918)
• Paul's Wife: or "The Ostriches" (1919)
• My Long Life (1939)