James Anthony "Tony" Simon, better known by his stage name Blockhead, is an American hip hop producer based in Manhattan, New York.
Aside from his solo efforts released on the Ninja Tune label, Blockhead is most associated with producing for Aesop Rock, a rapper for the indie hip hop labels Definitive Jux and Rhymesayers. He has also previously worked with rappers Cage, Hangar 18, Open Mike Eagle and Murs. He is also a member of the comedy hip hop group Party Fun Action Committee. According to him, his stage name comes from the shape of his head: "While it's not square, it's pretty close."