The 1951 U.S. National Championships (now known as the US Open) was a tennis tournament that took place on the outdoor grass courts at the West Side Tennis Club, Forest Hills in New York, United States. The tournament ran from 25 August until 5 September. It was the 71st staging of the U.S. National Championships, and the fourth Grand Slam tennis event of the year.

Frank Sedgman defeated Vic Seixas 6–4, 6–1, 6–1

Maureen Connolly defeated Shirley Fry 6–3, 1–6, 6–4