| 1955 U.S. National Championships | |
|---|---|
| Date | 2–11 September |
| Edition | 75th |
| Category | Grand Slam (ILTF) |
| Surface | Grass |
| Location | Chestnut Hill, Massachusetts Forest Hills, Queens, New York City United States |
| Venue | Longwood Cricket Club West Side Tennis Club |
| Champions | |
| Men's singles | |
 Tony Trabert[1] | |
| Women's singles | |
| Doris Hart | |
| Men's doubles | |
 Kosei Kamo / Atsushi Miyagi | |
| Women's doubles | |
| Louise Brough / Margaret Osborne duPont | |
| Mixed doubles | |
| Doris Hart / Vic Seixas | |
The 1955 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 City, United States. The tournament ran from 2 September until 11 September. It was the 75th staging of the U.S. National Championships, and the fourth Grand Slam tennis event of the year.
Finals
Men's singles
Tony Trabert (USA) defeated .svg.png.webp){kind=small}
Ken Rosewall (AUS) 9–7, 6–3, 6–3
Women's singles
Doris Hart (USA) defeated 
Patricia Ward (GBR) 6–4, 6–2
Men's doubles
Kosei Kamo (JPN) / Atsushi Miyagi (JPN) defeated Gerald Moss (USA) / Bill Quillian (USA) 6–2, 6–3, 3–6, 1–6, 6–4 [2]
Women's doubles
Louise Brough (USA) / Margaret Osborne duPont (USA) defeated Shirley Fry (USA) / Doris Hart (USA) 6–3, 1–6, 6–3 [3]
Mixed doubles
Doris Hart (USA) / Vic Seixas (USA) defeated Shirley Fry (USA) / Gardnar Mulloy (USA) 7–5, 5–7, 6–2 [4]