RKSV Groene Ster is a Dutch football club based in Heerlerheide. The club play its home games at Pronsebroek. The club colours, reflected in their crest, kit and name, are green and white. Formed on 2 November 1926, the club have mostly played in the lower tiers of Dutch football, but reached the final of the nationwide KNVB Cup in 1943–44, where they however lost to with a record 9–1 score to winners Willem II. This result still stands as the biggest defeat in a KNVB Cup final. The club are currently playing in the Derde Divisie (fourth tier).