The 1979 US Open was a tennis tournament played on outdoor hard courts at the USTA National Tennis Center in New York City in New York in the United States. It was the 99th edition of the US Open and the third Grand Slam tennis event of the year. The tournament was held from August 28 to September 9, 1979. John McEnroe and Tracy Austin won the singles titles.
John McEnroe defeated Vitas Gerulaitis 7–5, 6–3, 6–3 
- It was McEnroe's 1st career Grand Slam title.
Tracy Austin defeated Chris Evert 6–4, 6–3 
- It was Austin's 1st career Grand Slam title. Austin also became the youngest-ever US Open champion, aged 16 years and 9 months.
John McEnroe / Peter Fleming defeated Bob Lutz / Stan Smith 6–2, 6–4 
Betty Stöve / Wendy Turnbull defeated Billie Jean King Martina Navratilova 7–5, 6–3 
Greer Stevens / Bob Hewitt defeated Betty Stöve / Frew McMillan 6–3, 7–5 
Scott Davis defeated Jan Gunnarson 6–3, 6–1
Alycia Moulton defeated Mary Lou Piatek 7–6, 7–6