1991 US Open (tennis)

The 1991 US Open was a Grand Slam tennis tournament played on outdoor hard courts at the USTA National Tennis Center in Flushing Meadows, New York City, New York. It was the 111th edition of the US Open, and the fourth and final Grand Slam tournament of the year. The tournament took place from August 26 to September 8, 1991.

Stefan Edberg defeated Jim Courier in the men's singles final to win his first US Open title. Monica Seles defeated Martina Navratilova in the women's singles final to win her first US Open title.

The men's doubles title was won by John Fitzgerald and Anders Järryd, and the women's doubles title was won by Pam Shriver and Natalia Zvereva.

The mixed doubles title was won by Manon Bollegraf and Tom Nijssen.