| 2021 Karlsruhe Open | |
|---|---|
| Date | 7 – 12 September |
| Edition | 2nd |
| Category | WTA 125K series |
| Draw | 32S / 8D |
| Prize money | $115,000 |
| Surface | Clay |
| Location | Karlsruhe, Germany |
| Venue | TC Rüppurr |
| Champions | |
| Singles | |
 Mayar Sherif | |
| Doubles | |
 Irina Bara /  Ekaterine Gorgodze | |
The 2021 Karlsruhe Open (also known as the Liqui Moly Open for sponsorship reasons) was a professional tennis tournament played on outdoor clay courts. It was the 2nd edition of the tournament and part of the 2021 WTA 125K series, offering a total of $115,000 in prize money. It took place in Karlsruhe, Germany between 7 and 12 September 2021. The tournament did not take place in 2020 due to the COVID-19 pandemic.[1]
Mayar Sherif def. 
Martina Trevisan, 6–3, 6–2 Irina Bara / Ekaterine Gorgodze def. 
Katarzyna Piter / Mayar Sherif, 6–3, 2–6, [10–7]| Country | Player | Rank1 | Seed |
|---|---|---|---|
 FRA
|
Clara Burel | 92 | 1 |
 SVK
|
Anna Karolína Schmiedlová | 93 | 2 |
| EGY
|
Mayar Sherif | 96 | 3 |
| ITA
|
Martina Trevisan | 106 | 4 |
 SLO
|
Kaja Juvan | 109 | 5 |
 BEL
|
Maryna Zanevska | 113 | 6 |
 AUS
|
Astra Sharma | 114 | 7 |
| ROU
|
Irina Bara | 118 | 8 |
The following players received a wildcard into the singles main draw:
The following players qualified into the singles main draw:
Ana Bogdan → replaced by Maddison Inglis Elisabetta Cocciaretto → replaced by Jaqueline Cristian
Varvara Gracheva → replaced by 
Paula Ormaechea Polona Hercog → replaced by Ekaterine Gorgodze Kristína Kučová → replaced by Rebecca Šramková
Varvara Lepchenko → replaced by Grace Min Jasmine Paolini → replaced by Lucia Bronzetti
Nuria Párrizas Díaz → replaced by 
Katarina Zavatska
Kristýna Plíšková → replaced by 
Tamara Korpatsch
Arantxa Rus → replaced by Anastasia Gasanova Elena-Gabriela Ruse → replaced by 
Dalma Gálfi
Viktoriya Tomova → replaced by Cristina Bucșa
Zhang Shuai → replaced by Katarzyna Kawa| Country | Player | Country | Player | Rank1 | Seed |
|---|---|---|---|---|---|
| AUS
|
Astra Sharma | NED
|
Rosalie van der Hoek | 218 | 1 |
| GER
|
Vivian Heisen | BEL
|
Kimberley Zimmermann | 232 | 2 |
| POL
|
Katarzyna Piter | EGY
|
Mayar Sherif | 271 | 3 |
| ROU
|
Irina Bara | GEO
|
Ekaterine Gorgodze | 286 | 4 |
The following pair received a wildcard into the doubles main draw:
