Oliver Peter St John, 9th Earl of Orkney^{[lower-alpha 1]} (born 27 February 1938) is the current Earl of Orkney, and the son of Frederick Oliver St John whose parents were Sir Frederic Robert and Lady St. John (née Isabella Annie FitzMaurice).^[2][3]

He is a retired Canadian political scientist and Scottish peer. He was a lecturer at University College London, England, before moving to the University of Manitoba, Canada, where he rose to become professor of political studies. He retired from academia in 1998, the year he succeeded to the Earldom of Orkney, and was appointed a senior scholar by Manitoba.^[4][3][5]

In 1963, St John married Mary Juliet Scott-Brown.^[4] Together they had four children: one son and three daughters.^[4] Their son, Oliver Robert St John, Viscount Kirkwall, is heir to the earldom.^[3] His first marriage ended in divorce in 1985, and that year he married Mary Barbara Huck (née Albertson).^[4] His second marriage brought four step-children.^[4] As a male-line descendant of the 3rd Viscount Bolingbroke, he is also in remainder to this title.

• St. John, Peter (1977). Fireproof House to Third Option: Studies in the Theory and Practise of Canadian Foreign Policy. Winnipeg, Manitoba: University of Manitoba.
• St. John, Peter, ed. (1984). Mackenzie King to Philosopher King: Canadian Foreign Policy in a Modern Age. Winnipeg, Manitoba: University of Manitoba Press.
• St. John, Peter (1991). Air Piracy, Airport Security, and International Terrorism: Winning the War Against Hijackers. New York: Quorum Books. ISBN 978-0899304137.
• St. John, Peter, ed. (2005). From the Great War to the Global Village: A Window on the World. Winnipeg, Manitoba: Heartland Associates. ISBN 978-1896150239.