2025 NÖ Open
The 2025 NÖ Open was a professional tennis tournament played on clay courts. It was the fifth edition of the tournament which was part of the 2025 ATP Challenger Tour. It took place in Tulln an der Donau, Austria between 1 and 7 September 2025.
Singles main-draw entrants
Seeds
1 Rankings are as of 25 August 2025.Other entrants
The following players received wildcards into the singles main draw:The following player received entry into the singles main draw using a protected ranking:
The following player received entry into the singles main draw through the Next Gen Accelerator programme:
The following players received entry from the qualifying draw: