Cassel is a surname. Notable people with the surname include:
Christine K. Cassel, American physicianDavid Cassel, German historian and Jewish theologianErnest Cassel, British capitalistFelix Cassel, British Judge Advocate-General(Karl) Gustav Cassel, 1866–1945, Swedish economistHartwig Cassel, German chess promoterHenry B. Cassel, U.S. congressman from PennsylvaniaJack Cassel, Major League Baseball playerJean-Pierre Cassel, French actorMarcus Cassel, American football playerMatt Cassel, American football quarterbackPaulus Stephanus Cassel, 19th century Jewish convert to ChristianitySandra Cassel, American actressSeymour Cassel, American actorVincent Cassel, French actor