The 1939 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 7 until September 17.

It was the 59th staging of the U.S. National Championships and the fourth Grand Slam tennis event of the year.

[1] Bobby Riggs defeated Welby van Horn 6–4, 6–2, 6–4 Alice Marble defeated Helen Jacobs 6–0, 8–10, 6–4 Adrian Quist / John Bromwich defeated Jack Crawford / Harry Hopman 8–6, 6–1, 6–4 [2] Sarah Palfrey / Alice Marble defeated Kay Stammers / Freda James Hammersley 7–5, 8–6 [3] Alice Marble / Harry Hopman defeated Sarah Palfrey / Elwood Cooke 9–7, 6–1 [4]