The 1934 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 September 1 until September 12. It was the 54th staging of the U.S. National Championships and the fourth Grand Slam tennis event of the year. The men's and women's doubles events were held in Longwood Cricket Club in Chestnut Hill, Massachusetts.

Finals

Men's singles

🇬🇧 Fred Perry defeated 🇺🇸 Wilmer Allison 6–4, 6–3, 1–6, 8–6

Women's singles

🇺🇸 Helen Jacobs defeated 🇺🇸 Sarah Palfrey Cooke 6–1, 6–3

Men's doubles

🇺🇸 George Lott / 🇺🇸 Lester Stoefen defeated 🇺🇸 Wilmer Allison / 🇺🇸 John Van Ryn 6–4, 9–7, 3–6, 6–4

Women's doubles

🇺🇸 Helen Jacobs / 🇺🇸 Sarah Palfrey Cooke defeated 🇺🇸 Carolin Babcock / 🇺🇸 Dorothy Andrus 4–6, 6–3, 6–4

Mixed doubles

🇺🇸 Helen Jacobs / 🇺🇸 George Lott defeated 🇺🇸 Elizabeth Ryan / 🇺🇸 Lester Stoefen 4–6, 13–11, 6–2