John Murphy is an American lawyer and officer in the United States Naval Reserve. Andy Worthington reported on May 6, 2009, that Murphy was replacing Lawrence Morris as Chief Prosecutor of the Guantanamo military commissions, and that Morris was retiring from active duty. On December 12, 2008, while Murphy was an assistant Prosecutor in United States v. Omar Khadr, he had to present the case because lead Prosecutor Major Jeffrey Groharing was not present.