2018 Istanbul Open – Singles

Marin Čilić was the defending champion, but lost in the second round to Malek Jaziri.

Taro Daniel won his first ATP World Tour title, defeating Jaziri in the final, 7–6(7–4), 6–4.

Seeds
The top four seeds receive a bye into the second round. • # Marin Čilić (second round)

• #🇧🇦 Damir Džumhur (second round)

• #🇮🇹 Andreas Seppi (second round)

• # Aljaž Bedene (second round)

• #🇮🇹 Paolo Lorenzi (quarterfinals)

• #🇷🇸 Viktor Troicki (second round)

• #🇨🇿 Jiří Veselý (quarterfinals)

• # Nikoloz Basilashvili (first round)

Seeds
• # 🇮🇳 Ramkumar Ramanathan (qualifying competition)

• # 🇧🇾 Ilya Ivashka (first round)

• # 🇧🇷 Thiago Monteiro (qualified)

• # 🇸🇪 Elias Ymer (qualified)

• # 🇦🇹 Sebastian Ofner (first round)

• # Viktor Galović (first round)

• # 🇵🇱 Hubert Hurkacz (qualifying competition)

• # 🇮🇹 Stefano Napolitano (qualifying competition)

Qualifiers
• # 🇦🇷 Marco Trungelliti

• # 🇪🇸 Daniel Gimeno Traver

• # 🇧🇷 Thiago Monteiro

• # 🇸🇪 Elias Ymer