2021 Chicago Women's Open

The 2021 Chicago Women's Open was a tennis tournament held in Chicago, Illinois for female professional tennis players, and part of the 2021 WTA Tour. It was played on outdoor hard courts in the week prior to the 2021 U.S. Open. This marked the first time since 1997 that a WTA tournament was held in Chicago.

Singles

 * 🇺🇦 Elina Svitolina def. 🇫🇷 Alizé Cornet, 7–5, 6–4.

This was Svitolina's sixteenth WTA Tour singles title, and first of the year.

Doubles

 * 🇺🇦 Nadiia Kichenok / 🇷🇴 Raluca Olaru def. 🇺🇦 Lyudmyla Kichenok / 🇯🇵 Makoto Ninomiya, 7–6(8–6), 5–7, [10–8].

Seeds

 * Rankings are as of August 16, 2021.

Other entrants
The following players received wildcards into the main draw:
 * 🇨🇦 Françoise Abanda
 * 🇨🇦 Katherine Sebov
 * 🇺🇦 Elina Svitolina
 * 🇺🇸 Venus Williams

The following players received entry from the qualifying draw:
 * 🇷🇴 Ana Bogdan
 * 🇰🇿 Zarina Diyas
 * 🇺🇸 Quinn Gleason
 * Aldila Sutjiadi

The following player received entry as a lucky loser:
 * 🇫🇷 Clara Burel

Withdrawals

 * Before the tournament
 * 🇮🇹 Camila Giorgi → replaced by 🇫🇷 Clara Burel
 * 🇩🇪 Andrea Petkovic → replaced by 🇷🇺 Varvara Gracheva
 * 🇰🇿 Elena Rybakina → replaced by 🇯🇵 Misaki Doi
 * 🇦🇺 Ajla Tomljanović → replaced by 🇫🇷 Fiona Ferro

Seeds

 * Rankings are as of August 16, 2021.

Withdrawals

 * Before the tournament
 * 🇷🇺 Anastasia Potapova / 🇬🇧 Heather Watson → replaced by Bárbara Gatica / 🇧🇷 Rebeca Pereira