The 2023 Heilbronner Neckarcup was a professional tennis tournament played on clay courts.

It was the ninth edition of the tournament which was part of the 2023 ATP Challenger Tour.

It took place in Heilbronn, Germany between 5 and 11 June 2023.

[1] 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: The following player received entry as a lucky loser: