Cornelis Jan "Kees" Hazevoet (born 15 March 1948) is a Dutch ornithologist and former professional jazz musician. He played piano, clarinet, and sometimes trumpet during his musical career, during which he was among the leading figures in the introduction of free jazz to the Netherlands. He is now curator of birds at the University of Lisbon's natural history museum, and an expert on the birds and other fauna of Cape Verde.