Ilse Koch (; née Margarete Ilse Köhler; 22 September 1906 – 1 September 1967) was the wife of Karl-Otto Koch, commandant of the Nazi concentration camps Buchenwald (1937–1941) and Majdanek (1941–1943). In 1947, she became one of the first prominent Nazis to be tried by the U.S. military.