Oleg Vladimirovich Penkovsky (; 23 April 1919 – 16 May 1963), codenamed HERO, was a Soviet military intelligence (GRU) colonel during the late 1950s and early 1960s. Penkovsky informed the United Kingdom about the Soviet emplacement of missiles in Cuba, which provided both the UK and the United States with the precise knowledge necessary to address rapidly developing military tensions with the Soviet Union.