2021 Nottingham Trophy – Men's singles

Marcos Baghdatis was the defending champion but retired from professional tennis in 2019.

Alex Bolt won the title after defeating Kamil Majchrzak 4–6, 6–4, 6–3 in the final.

Seeds
• # 🇫🇷 Richard Gasquet (quarterfinals, retired)

• # 🇰🇷 Kwon Soon-woo (second round)

• # 🇮🇹 Andreas Seppi (first round)

• # Kevin Anderson (first round)

• # 🇸🇪 Mikael Ymer (first round)

• # 🇰🇿 Mikhail Kukushkin (first round)

• # 🇯🇵 Yūichi Sugita (first round)

• # 🇯🇵 Yasutaka Uchiyama (first round)