The 2013 K League Classic was the 31st season of the top division of South Korean professional football.

Its fixtures were announced on 30 January,[1] and began on 2 March.

Restricting the number of foreign players strictly to four per team, including a slot for a player from AFC countries.

Leaders Qualification for Champions League Qualification for relegation play-offs Relegation to K League Challenge

Sangju Sangmu won 4–2 on aggregate and were promoted to the K League Classic, while Gangwon FC were relegated to the K League Challenge.