| Date: | 5–11 June |
| Edition: | 9th |
| Surface: | Clay |
| Location: | Heilbronn, Germany |
| Champs: |  Matteo Arnaldi |
| Champd: | Constantin Frantzen / Hendrik Jebens |
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]
See main article: 2023 Heilbronner Neckarcup – Singles.
Matteo Arnaldi def. 
Facundo Díaz Acosta 7–6(7–4), 6–1.See main article: 2023 Heilbronner Neckarcup – Doubles.
Victor Vlad Cornea / 
Philipp Oswald 7–6(9–7), 6–4.| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| Italy | Marco Cecchinato | 72 | 1 | |
 Spain | Jaume Munar | 81 | 2 | |
 Colombia | Daniel Elahi Galán | 91 | 3 | |
| Austria | Dominic Thiem | 92 | 4 | |
| Italy | Matteo Arnaldi | 106 | 5 | |
 Hungary | Fábián Marozsán | 115 | 6 | |
| Oscar Otte | 120 | 7 | ||
| Pavel Kotov | 121 | 8 |
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:
