2021 Open Castilla y León – Singles

Nicola Kuhn was the defending champion but chose not to defend his title.

Benjamin Bonzi won the title after defeating Tim van Rijthoven 7–6(12–10), 3–6, 6–4 in the final.

Seeds
• # 🇪🇸 Feliciano López (quarterfinals)

• # 🇫🇷 Benjamin Bonzi (champion)

• # 🇫🇷 Grégoire Barrère (withdrew)

• # Marc-Andrea Hüsler (first round)

• # Frederico Ferreira Silva (first round, retired)

• # 🇫🇷 Quentin Halys (first round)

• # 🇫🇷 Mathias Bourgue (quarterfinals)

• # 🇹🇷 Altuğ Çelikbilek (quarterfinals)

• # 🇹🇷 Cem İlkel (second round)