Communist League of Luxembourg (, ), was an anti-revisionist Marxist-Leninist political organization in Luxembourg. Forerunner of the KBL was the (ASSOSS). ASSOSS was originally a left liberal organization founded in 1912 which moved leftward in the sixties. In 1969, it was transformed in the radical (GSR). After the split of the trotskyist (LCR) in 1970, the majority of GSR was renamed in KBL in 1972. In 1972, (KGL) split from KBL. In 1975, (KOL/ML) broke away but returned in 1978.
In 1979, KBL was the driving force behind the electoral which won 0,7 p.c. in the parliamentary elections. In the same year, the majority of KBL left and founded the short-lived organization . The KBL ceased activities in 1980.
The secretary of KBL was Charles Doerner.