John Julius Cooper, 2nd Viscount Norwich (born 15 September 1929), known as John Julius Norwich, is a British historian, travel writer and television personality and the son of the Conservative politician and diplomat Duff Cooper, who in 1952 was created Viscount Norwich, and of Lady Diana Cooper, a celebrated beauty and society figure.

Norwich was educated at Upper Canada College, Toronto, at Eton College and at the University of Strasbourg (while his father was British Ambassador in Paris). He served in the Royal Navy before taking a degree in French and Russian at Oxford University. He then joined the British Foreign Service, serving in Yugoslavia and Lebanon, and as a member of British delegation to the Disarmament Conference in Geneva.

In 1964 Norwich left government service to become a writer. His best-known works include two books on Norman Sicily, The Normans in the South and The Kingdom in the Sun (later republished in one volume as The Normans in Sicily); Mount Athos (with Reresby Sitwell ); Sahara; A History of Venice; The Architecture of Southern England; Fifty Years of Glyndebourne; and A Taste for Travel.

Norwich's recent works include Byzantium: The Early Centuries, Byzantium: The Apogee and Byzantium: The Decline and Fall; A Short History of Byzantium; a work of humor, The Twelve Days of Christmas; and Shakespeare's Kings; and Venice: A Traveller's Companion. He has also served as editor of series such as Great Architecture of the World, The Italian World, The New Shell Guides to Great Britain and The Oxford Illustrated Encyclopaedia of Art.

Norwich has worked extensively in radio and television. He was host of the popular BBC radio panel game My Word! for four years. He has written and presented some 30 television documentaries, including The Fall of Constantinople, Napoleon's Hundred Days, Cortés and Montezuma, The Antiquities of Turkey, The Gates of Asia, Maximilian of Mexico, Toussaint l'Ouverture of Haiti, The Knights of Malta and The Death of the Prince Imperial in the Zulu War.

Norwich has also worked for various charitable projects. He is Chairman of the Venice in Peril Fund, Co-Chairman of the World Monuments Fund, and a Vice-President of the National Association of Decorative and Fine Art Societies. For many years he was a member of the Executive Committee of the National Trust, and also served on the Board of the English National Opera.