The 2023 Ostra Group Open was a professional tennis tournament played on clay courts. It was the 20th edition of the tournament which was part of the 2023 ATP Challenger Tour. It took place in Ostrava, Czech Republic between 24 and 30 April 2023.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 United Kingdom | Ryan Peniston | 158 | 1 | |
| Ivan Gakhov | 162 | 2 | ||
 Czech Republic | Vít Kopřiva | 165 | 3 | |
 France | Geoffrey Blancaneaux | 175 | 4 | |
 Italy | Riccardo Bonadio | 179 | 6 | |
 Ukraine | Oleksii Krutykh | 180 | 7 | |
 Bosnia and Herzegovina | Damir Džumhur | 202 | 8 | |
| Czech Republic | Dalibor Svrčina | 203 | 9 |
The following players received wildcards into the singles main draw:
The following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
Guido Andreozzi
Àlex Martí Pujolràs Patrik Rikl
Khumoyun Sultanov Zdeněk Kolář def. 
Máté Valkusz 6–3, 6–2.See main article: 2023 Ostra Group Open – Doubles.
Robert Galloway / 
Miguel Ángel Reyes-Varela def. Guido Andreozzi / Guillermo Durán 7–5, 7–6(7–5).