- Kampuchea
- see Cambodia - Kerin, Dave
- Khrushchev, Nikita (1894 - 1971)
- Khrushchev's secret speech
- see Twentieth Congress of the Communist Party of the Soviet Union (1956) - Kirsner, Douglas
- Knights of Labor (1869 - c. 1900)
- Korean War
- Kropotkin, Peter (1892 - 1921), Activist and Theorist
- Kuhn, Gabriel