Simon Peter Gillis (April 6, 1875 – January 14, 1964) was an American track and field athlete, a member of the New York Athletic Club, and the New York City Police Department. He was one of a group of athletes known as the Irish Whales and frequently kept company with members of the Irish American Athletic Club. He competed in weight throwing events in the 1904, 1908 and 1912 Summer Olympics.