The 1965 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 1 September until 12 September. It was the 85th staging of the U.S. National Championships, and the fourth Grand Slam tennis event of 1965.

Finals

Men's singles

🇪🇸 Manuel Santana defeated 🇿🇦 Cliff Drysdale 6–2, 7–9, 7–5, 6–1

Women's singles

🇦🇺 Margaret Smith defeated 🇺🇸 Billie Jean Moffitt 8–6, 7–5

Men's doubles

🇦🇺 Roy Emerson / 🇦🇺 Fred Stolle defeated 🇺🇸 Frank Froehling / 🇺🇸 Charles Pasarell 6–4, 10–12, 7–5, 6–3

Women's doubles

🇺🇸 Carole Graebner / 🇺🇸 Nancy Richey defeated 🇺🇸 Billie Jean Moffitt / 🇺🇸 Karen Susman 6–4, 6–4

Mixed doubles

🇦🇺 Margaret Smith / 🇦🇺 Fred Stolle defeated 🇦🇺 Judy Tegart / 🇺🇸 Frank Froehling 6–2, 6–2