Guus Janssen, born May 13, 1951, in Heiloo, is a Dutch composer and pianist. He studied piano and composition at the Amsterdam Conservatory with Ton de Leeuw and Jaap Spaanderman. Since the early 1980s he has performed mainly with ensembles playing his own compositions or improvisations and has appeared at festivals such as the North Sea Jazz Festival and the Holland Festival. He has been recognized with numerous awards, including the Boy Edgar Award in 1981 and the Matthijs Vermeulen Award in 1984. His recordings include albums such as Klankast (1992) and Lighter (1995). Janssen has collaborated with musicians including John Zorn, Theo Loevendie, Han Bennink, and George Lewis. In 1988 he formed the Janssen/Glerum/Janssen trio with his brother, drummer Wim Janssen, and bassist Ernst Glerum, which toured internationally. His compositions have been performed by ensembles such as the Schönberg Ensemble and the Kronos Quartet.