Ashleigh Barty defeated Aryna Sabalenka in the final, 3–6, 6–0, 6–3 to win the women's singles tennis title at the 2021 Stuttgart Open.

It marked her 11th career Women's Tennis Association (WTA) singles title and her second on clay.

1 to win the title since Justine Henin in 2007.

[1] Petra Kvitová was the defending champion from when the tournament was last held in 2019,[2] but lost in the quarterfinals to Elina Svitolina.

[3] The top four seeds received a bye into the second round.