Leigh Diffey (born 3 March 1971) is an Australian American auto racing commentator. His career began calling motorcycle races in his home country before moving to the United Kingdom to cover other forms of motorsport. Diffey then moved to the United States to join Speed Channel, while simultaneously working for Network Ten in Australia. Since 2013, he has served as a play-by-play announcer and studio host with NBC Sports in the United States.