| 1912 U.S. National Championships | |
|---|---|
| Date | August 19–26 (M) June 10–15 (W)  | 
| Edition | 32nd | 
| Category | Grand Slam | 
| Surface | Grass (outdoor) | 
| Location | Newport, R.I., United States (M)  Philadelphia, PA, United States (W)  | 
| Venue | Newport Casino  (M) Philadelphia Cricket Club (W)  | 
| Champions | |
| Men's singles | |
| Women's singles | |
| Men's doubles | |
| Women's doubles | |
| Mixed doubles | |
The 1912 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 19 until August 26 while the women's singles and doubles championship took place from June 10 to June 15 at the Philadelphia Cricket Club in Chestnut Hill. It was the 32nd staging of the U.S. National Championships, and the second Grand Slam tennis event of the year. The challenge round was abolished in this edition, thus requiring all participants, including the defending champion, to play the main draw.
Finals
Men's singles
 Maurice McLoughlin defeated 
 Wallace F. Johnson  3–6, 2–6, 6–2, 6–4, 6–2
Women's singles
 Mary Browne defeated 
 Eleonora Sears  6–4, 6–2
Men's doubles
 Maurice McLoughlin / 
 Tom Bundy defeated 
 Raymond Little / 
 Gustave F. Touchard 3–6, 6–2, 6–1, 7–5
Women's doubles
 Mary Browne / 
 Dorothy Greene defeated 
 Maud Barger-Wallach / 
 Mrs. Frederick Schmitz 6–2, 5–7, 6–0
Mixed doubles
 Mary Browne / 
 R. Norris Williams defeated 
 Eleonora Sears / 
 William Clothier 6–4, 2–6, 11–9