1979 US Open (tennis)

The 1979 US Open was a tennis tournament played on outdoor hard courts at the USTA National Tennis Center in Flushing Meadows, New York City, New York. It was the 99th edition of the US Open and the third Grand Slam event of the year. The tournament was held from August 28 to September 9, 1979.

The singles champions were John McEnroe, who defeated Vitas Gerulaitis in the men's final, and Tracy Austin, who defeated Chris Evert in the women's final. It was McEnroe's first Grand Slam singles title and Austin's first US Open title.

The men's doubles champions were John McEnroe and Peter Fleming, who defeated Bob Lutz and Stan Smith. The women's doubles champions were Betty Stöve and Wendy Turnbull, who defeated Billie Jean King and Martina Navratilova. The mixed doubles champions were Greer Stevens and Bob Hewitt, who defeated Betty Stöve and Frew McMillan.

This edition was notable for being the first US Open to be played on hard courts, having previously been played on clay. The change was made to provide a more consistent playing surface and to better accommodate the growing popularity of hard court tennis. The tournament also featured several upsets, including the early exits of top seeds Björn Borg and Martina Navratilova.