1917 U.S. National Championships – Men's singles

Robert Lindley Murray defeated Nathaniel W. Niles 5–7, 8–6, 6–3, 6–3 in the final to win the men's singles tennis title at the 1917 U.S. National Championships. The event was held at the West Side Tennis Club in Forest Hills, New York. The tournament was renamed National Patriotic Tournament in support of the war effort. No trophies were handed out to the winners and the entrance fees were dedicated to the American Red Cross.