The South Korea national football team (Korean: 대한민국 축구 국가대표팀; recognized as Korea Republic by FIFA) represents South Korea in men's international football and is governed by the Korea Football Association. South Korea has developed and emerged as a major football power in Asia since the 1980s and is historically the most successful Asian football team, having participated in nine consecutive and ten overall FIFA World Cup tournaments, the most for any Asian country. Despite initially going through five World Cup tournaments without winning a match, South Korea became the only Asian team to reach the semi-final stages when they co-hosted the 2002 tournament with Japan. South Korea also won two AFC Asian Cup titles, and finished as runners-up on four occasions. Furthermore, the team won three gold medals and three silver medals at the senior Asian Games. The team is commonly nicknamed the "Reds" by both fans and the media due to the color of their primary kit. The national team's supporting group is officially referred to as the Red Devils.

Korea (Joseon) was not introduced to the sport of association football until the late 19th century; it is often said that football in Korea dates to 1882, when the Royal Navy sailors from HMS Flying Fish played a game while their vessel was visiting the Incheon Port. Korea became a Japanese colony in 1905 and was annexed into it outright in 1910.

In 1921, the first All Joseon Football Tournament was held, and in 1928, the Joseon Football Association was organized, which created a foundation to disseminate and develop football in Korea. Korean teams participated in competitions with Japanese teams from around 1926; Joseon Football Club became a de facto national team for Koreans, and won the 1935 Emperor's Cup. Koreans also played for the Japanese national team, most notably Kim Yong-sik who played for Japan at the 1936 Summer Olympics.