Willem Gillisz Kool (1608 - 1666), was a Dutch Golden Age painter.
He was born in Haarlem and entered the Haarlem Guild of St. Luke in 1638.[1] In the same year he married Cornelia van der Molen, daughter of Jan Gerritsen van der Molen, on 17 januari 1638. He is known for landscapes and died in Haarlem.[1]