The 2018 South Korean by-elections was held in South Korea on 13 June 2018, coinciding with the local elections. 12 seats to the National Assembly of South Korea were contested.[1]
South Chungcheong Cheonan C District: Yang Seung-cho (Democratic), due to Yang's resignation from the National Assembly, to run 2018 South Chungcheong Province gubernatorial election.
North Gyeongsang Gimcheon District: Lee Cheol-woo (Liberty Korea), due to Lee's resignation from the National Assembly, to run 2018 North Gyeongsang Province gubernatorial election.
South Gyeongsang Gimhae B District: Kim Kyung-soo (Democratic), due to Kim's resignation from the National Assembly, to run 2018 South Gyeongsang Province gubernatorial election.