The South Korean football league system contains two professional leagues, two semi-professional leagues, and various amateur leagues for South Korean football clubs.
The top-tier league of the system is the K League 1, which was founded in 1983. The second-tier professional league was founded in 2013 under the name of K League 2. Below the two professional leagues, there are two semi-professional leagues, namely the K3 League and the K4 League.
South Korean female footballers participate at the WK League, the sole semi-professional league founded in 2009.
The Korean National Semi-Professional Football League was the first-ever semi-professional football league in South Korea, and was contested between works teams and military teams from 1964 to 2002. It became the second-tier league after the K League was established in 1983, and was replaced by the Korea National League in 2003.
The first official amateur league, regarded as the third-tier league, was founded in 2007, and was named the K3 League. The National League and the amateur K3 League were demoted to the third and fourth-tier leagues after the K League 2 appeared in 2013.
In 2017, the amateur K3 League was divided into two divisions, the K3 League Advanced and the K3 League Basic. They were renamed the K3 League and the K4 League respectively when being relaunched as semi-professional leagues in 2020. The National League was merged into the new K3 League at the same time.
A system of promotion and relegation has been realised within each of three classes (professional, semi-professional and amateur) from the beginning, but there was no promotion and relegation between classes until 2025. The Korea Football Association (KFA) went over their plans to unify the league system including promotions and relegations between three classes for a long time. Since 2026, the KFA are partially allowing a play-off between the K League 2 and the K3 League as well as promotion from the K5 League to the K4 League (without relegation from K4 to K5), according to the results of their examination.
Outside this league structure, there are the U-League and the R League, contested by university teams and reserve teams respectively.
K League, K3 League, K4 League, and some K5 League clubs qualify for the Korea Cup.
The Korean League Cup was open to K League teams only, whilst National League teams could compete in the National League Championship. They were abolished in 2012 and 2020, respectively.
The K League Super Cup is contested between the K League 1 champions and the Korea Cup champions.
As of 2026, the top two K League 1 clubs and the Korea Cup champions qualify for the AFC Champions League Elite. If the Korea Cup champions finish outside the top four at the K League 1, they participate at the AFC Champions League Two instead of the third-placed team of the K League 1.