Helsingin Jalkapalloklubi, commonly known as HJK Helsinki, or simply as HJK, is a professional football club based in Helsinki, Finland.
Generally considered as Finland's biggest club, HJK is the most successful Finnish club in terms of championship titles with 31. The club has also won 14 Finnish Cups and 5 Finnish League Cups. Many of Finland's most successful players have played for HJK before moving abroad. The club has also similar success with women's Kansallinen Liiga.
HJK is the only Finnish club that has participated in the UEFA Champions League group stage. In 1998, they beat Metz in the play-off round to clinch their place in the competition for the following season. HJK have also participated in the group stages of the UEFA Europa League in 2014–15 and 2022–23 respectively. The club's highest score in a European competition came during the 2011–12 season, with a 13–0 aggregate victory over Welsh champions Bangor City, which included a 10–0 home win.
HJK's traditional kit colours have long been blue and white striped shirts with blue shorts and socks. The club's crest has been nearly untouched for a century, it has only undergone one minor font change in order to modernize it.