The 2021 Berkeley Tennis Club Challenge was a professional women's tennis tournament played on outdoor hard courts. It was the third edition of the tournament which was part of the 2021 ITF Women's World Tennis Tour. It took place in Berkeley, California, United States between 27 September and 3 October 2021.
Singles main-draw entrants
Seeds
1 Rankings are as of 20 September 2021.
Other entrants
The following players received wildcards into the singles main draw: Reese Brantmeier Ellie Douglas Victoria Duval Paola Expósito Díaz Delgado
The following player received entry using a protected ranking: Louisa Chirico
The following player received entry as a special exempt: Kayla Day
The following players received entry from the qualifying draw: Alexandra Bozovic Sophie Chang Jada Hart Haruka Kaji Maria Kozyreva Hiroko Kuwata Maegan Manasse Emma Navarro