2021 Nottingham Open – Men's singles

Dan Evans was the defending champion but lost in the quarterfinals to Denis Kudla.

Frances Tiafoe won the title after defeating Kudla 6–1, 6–3 in the final.

Seeds
• # 🇬🇧 Dan Evans (quarterfinals)

• # 🇺🇸 Frances Tiafoe (champion)

• # 🇮🇹 Andreas Seppi (quarterfinals)

• # Kevin Anderson (quarterfinals)

• # 🇺🇸 Mackenzie McDonald (first round)

• # 🇺🇸 Denis Kudla (final)

• # 🇧🇦 Damir Džumhur (first round)

• # 🇵🇱 Kamil Majchrzak (semifinals)