The Namyangju massacre (Korean: 남양주 민간인학살 Hanja: 南楊州民間人虐殺 Namyangju civilian massacre) was a mass killing conducted by South Korean police and local militia forces between October 1950 and early 1951 in Namyangju, Gyeonggi-do district of South Korea. More than 460 people were summarily executed, including at least 23 children under the age of 10. After the victory of the Second Battle of Seoul, South Korean authorities arrested and summarily executed several individuals along with their families on suspicion of sympathizing with North Korea. During the massacre, South Korean Police conducted the Goyang Geumjeong Cave massacre in Goyang near Namyangju.