- Source: 2023 Ostra Group Open
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.
Singles main-draw entrants
= Seeds
=1 Rankings are as of 17 April 2023.
= Other entrants
=The following players received wildcards into the singles main draw:
Jakub Menšík
Gaël Monfils
Jiří Veselý
The following players received entry into the singles main draw as alternates:
Shintaro Mochizuki
Vitaliy Sachko
The following players received entry from the qualifying draw:
Guido Andreozzi
Àlex Martí Pujolràs
Rudolf Molleker
Patrik Rikl
Henri Squire
Khumoyun Sultanov
Champions
= Singles
=Zdeněk Kolář def. Máté Valkusz 6–3, 6–2.
= Doubles
=Robert Galloway / Miguel Ángel Reyes-Varela def. Guido Andreozzi / Guillermo Durán 7–5, 7–6(7–5).