2023 Oeiras Indoors II – Singles

Joris De Loore was the defending champion but lost in the final to Arthur Fils.

Fils won the title after defeating De Loore 6–1, 7–6(7–4) in the final.

Seeds
• # 🇱🇹 Ričardas Berankis (semifinals)

• # 🇬🇧 Jay Clarke (second round)

• # 🇮🇹 Matteo Gigante (first round)

• # 🇫🇷 Arthur Fils (champion)

• # 🇷🇸 Hamad Međedović (first round)

• # 🇫🇷 Harold Mayot (first round)

• # 🇪🇸 Nikolás Sánchez Izquierdo (first round)

• # 🇨🇦 Steven Diez (first round)