The 2021 BNP Paribas Polish Cup was a professional tennis tournament played on clay courts. It was the 1st edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Warsaw, Poland between 23 and 29 August 2021.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| Daniel Altmaier | 122 | 1 | ||
 Slovakia | Jozef Kovalík | 125 | 2 | |
| Slovakia | Lukáš Klein | 252 | 3 | |
 France | Tristan Lamasine | 257 | 4 | |
| Duje Ajduković | 258 | 5 | ||
| Nicolás Jarry | 262 | 6 | ||
 Ukraine | Vitaliy Sachko | 263 | 7 | |
 Bosnia and Herzegovina | Mirza Bašić | 269 | 8 |
The following players received wildcards into the singles main draw:
The following player received entry into the singles main draw using a protected ranking:
Jeroen VannesteThe following players received entry from the qualifying draw:
See main article: 2021 BNP Paribas Polish Cup – Singles.
Camilo Ugo Carabelli def. Nino Serdarušić 6–4, 6–2.See main article: 2021 BNP Paribas Polish Cup – Doubles.
Hans Hach Verdugo / Miguel Ángel Reyes-Varela def. Vladyslav Manafov / 
Piotr Matuszewski 6–4, 6–4.
