Pieter Mulier I, was a Dutch Golden Age painter.
According to the RKD he married in 1635, and became a member of the Haarlem Guild of St. Luke in 1638. He is known for Italianate landscapes and seascapes in the manner of Simon de Vlieger and Jan van Goyen. He was the teacher of his son Pieter Mulier II and Frans de Hulst.