The 1911 U.S. National Championships (now known as the US Open) took place on the outdoor grass courts at the Newport Casino in Newport, United States. The men's singles tournament ran from August 21 until September 3 while the women's singles and doubles championship took place from June 12 to June 17 at the Philadelphia Cricket Club in Chestnut Hill. It was the 31st staging of the U.S. National Championships, and the second Grand Slam tennis event of the year. William Larned won the men's singles championship for a record seventh and final time.
See main article: 1911 U.S. National Championships – Men's singles. 
William Larned (USA) defeated Maurice McLoughlin (USA) 6–4, 6–4, 6–2
See main article: 1911 U.S. National Championships – Women's singles. Hazel Hotchkiss (USA) defeated Florence Sutton (USA) 8–10, 6–1, 9–7
Raymond Little (USA) / Gustav Touchard (USA) defeated Fred Alexander (USA) / Harold Hackett (USA) 7–5, 13–15, 6–2, 6–4
Hazel Hotchkiss (USA) / Eleonora Sears (USA) defeated Dorothy Green (USA) / Florence Sutton (USA) 6–4, 4–6, 6–2
Hazel Hotchkiss (USA) / Wallace F. Johnson (USA) defeated Edna Wildey (USA) / Herbert M. Tilden (USA) 6–4, 6–4