Terence John Temple Hamilton-Temple-Blackwood, 2nd Marquess of Dufferin and Ava DL JP (16 March 1866 – 7 February 1918), styled Lord Terence Blackwood between 1888 and 1900 and Earl of Ava between 1900 and 1902, was a British diplomat.^[1]

Lord Dufferin was the second son of Frederick Hamilton-Temple-Blackwood, 1st Marquess of Dufferin and Ava and Hariot Hamilton-Temple-Blackwood, Marchioness of Dufferin and Ava.^[2][3] His father was Governor General of Canada of in the 1870s and Viceroy and Governor-General of India in the 1880s and his mother was known for leading an initiative to improve medical care for women in British India.^[4]

His paternal grandparents were Price Blackwood, 4th Baron Dufferin and Claneboye and Helen Blackwood, Baroness Dufferin and Claneboye (a granddaughter of the playwright Richard Brinsley Sheridan), members of the Ascendancy, Ireland's Anglo-Irish aristocracy. His maternal grandfather was Archibald Hamilton-Rowan of Killyleagh Castle (now Northern Ireland).

As a younger son, he was not expected to inherit the title, but on the death of his brother Archibald, Earl of Ava at the Siege of Ladysmith in the Second Boer War on 11 January 1900,^[5] he became the heir and assumed the courtesy title Earl of Ava himself before succeeding his father in 1902.^[6]

From 1891 to 1918, he worked as a clerk at the Foreign Office, Second Secretary of the Diplomatic Service and a Justice of the Peace and Deputy Lieutenant for County Down.^[7]

Lord Dufferin married Florence "Flora" Davis,^[8] a rich American singer who was the daughter of New York banker John Hagy Davis,^[9] of 24 Washington Square, New York City,^[10][11] in 1893.^[12] Together, they were the parents of three daughters:^[13]

• Lady Doris Gwendoline Hamilton-Temple-Blackwood (1895–1984), who married Captain Cecil Bernard Gunston, MC (1885–1934) of the Coldstream Guards, son of Major Bernard Gunston, formerly of the 5th Dragoon Guards, on 19 October 1922.^[13]
• Lady Ursula Florence Hamilton-Temple-Blackwood (9 Feb 1899-13 Feb 1982), who married Arthur Swithin Newton Horne, formerly of The King's Own Royal Border Regiment and Government Secretary of the Federated Malay States (d. 1954).^[13]
• Lady Patricia Ethel Hamilton-Temple-Blackwood (1902–1983), who married Henry Russell, the former director of the Boston Opera Company and the son of musician Henry Russell, on 11 June 1926.^[13][14]

Lord Dufferin died from pneumonia on 7 February 1918 and was buried at the Dufferin ancestral seat of Clandeboye, County Down.^[15] The marquessate passed to his youngest brother, Lord Frederick Blackwood.^[16] Two years after his death his widow married again, to Richard George Penn Curzon, 4th Earl Howe, and died on 14 April 1925.^[17][18]