Racing Club de Lens ([ʁasiŋ klœb də lɑ̃s], commonly referred to as RC Lens or simply Lens) is a French professional football club based in the northern city of Lens in the Pas-de-Calais department. Its nickname, les sang et or (the blood and gold), comes from its traditional colours of red and gold. Their traditional rivals are their northern neighbours Lille, with whom they contest the Derby du Nord.

The club was established in 1906 in Lens by local students who enjoyed playing football on the city's Place Verte (the current Place de la République). The name "Racing Club de Lens" was chosen as a reference to Racing Club de Roubaix and Racing Club de France, both popular clubs at the time.

The club's first board of directors was formed by the parents of those students. The club originally played in green and black to represent the founding location; they wore green to represent the name of the home pitch, "Verte", (meaning 'green' in French), and black to represent the omnipresence of the coal mining industry in the surrounding area.

Between 1907 and 1912, the players were forced to change home grounds twice before settling at the Parc des Glissoires, situated between Avion and Lens.