2023 Koblenz Open – Singles

Tomáš Macháč was the defending champion but chose not to defend his title.

Roman Safiullin won the title after defeating Vasek Pospisil 6–2, 7–5 in the final.

Seeds
• # 🇨🇳 Zhang Zhizhen (second round)

• # Roman Safiullin (champion)

• # 🇨🇦 Vasek Pospisil (final)

• # 🇩🇪 Maximilian Marterer (quarterfinals, retired)

• # 🇫🇷 Hugo Grenier (second round)

• # 🇬🇧 Liam Broady (second round)

• # 🇫🇷 Alexandre Müller (quarterfinals)

• # Gijs Brouwer (first round)