The 1964 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 13 September. It was the 84th staging of the U.S. National Championships, and the fourth Grand Slam tennis event of 1964.

Finals

Men's singles

🇦🇺 Roy Emerson defeated 🇦🇺 Fred Stolle 6–4, 6–1, 6–4

Women's singles

🇧🇷 Maria Bueno defeated 🇺🇸 Carole Caldwell Graebner 6–1, 6–0

Men's doubles

🇺🇸 Chuck McKinley / 🇺🇸 Dennis Ralston defeated 🇬🇧 Graham Stilwell / 🇬🇧 Mike Sangster 6–3, 6–2, 6–4

Women's doubles

🇺🇸 Billie Jean Moffitt / 🇺🇸 Karen Susman defeated 🇦🇺 Margaret Smith / 🇦🇺 Lesley Turner 3–6, 6–2, 6–4

Mixed doubles

🇦🇺 Margaret Smith / 🇦🇺 John Newcombe defeated 🇦🇺 Judy Tegart / 🇺🇸 Ed Rubinoff 10–8, 4–6, 6–3