2021 Miami Open – Women's singles
| Women's singles | |
|---|---|
| 2021 Miami Open | |
| Champion | Ashleigh Barty |
| Runner-up | Bianca Andreescu |
| Score | 6–3, 4–0, ret. |
| Draw | 96 |
| Seeds | 32 |
Defending champion Ashleigh Barty won the women's singles tennis title at the 2021 Miami Open after Bianca Andreescu retired from the final with the scoreline at 6–3, 4–0. Barty saved a match point en route to the title, in the second round against Kristína Kučová.
Barty and Naomi Osaka were in contention for the WTA No. 1 singles ranking. Barty retained the top ranking by winning the title after Osaka lost to Maria Sakkari in the quarterfinals, ending a 23-match winning streak dating to the 2020 Cincinnati Masters.