The 2021 US Open was held on outdoor hard courts at the USTA Billie Jean King National Tennis Center in Flushing Meadows, New York City.

Daniil Medvedev won the men's singles title.

Emma Raducanu won the women's singles title, becoming the first qualifier, male or female, to reach a major final and win a major title.

Both Dylan Alcott and Diede de Groot achieved the Golden Slam in wheelchair quad singles and wheelchair women's singles, respectively, by winning all four majors and the Paralympics in 2021. Alfie Hewett and Gordon Reid also achieved the Grand Slam in wheelchair men's doubles by winning all four majors in 2021.

Novak Djokovic lost to Medvedev in the final.

The 2020 Summer Paralympics were held during the first week of the tournament.

This was the first Major tournament since the 1997 Australian Open not to feature Roger Federer, Rafael Nadal, Serena Williams, or Venus Williams in the main singles draw.

The United States Tennis Association allowed the return of spectators after the 2020 tournament was held behind closed doors due to the COVID-19 pandemic in New York. Due to a surge in COVID-19 cases resulting from the delta variant of the virus, spectators had to present a negative COVID-19 test or proof of vaccination in order to be allowed to enter the grounds.