1971 Monte Carlo Open – Men's singles

The  1971 Monte Carlo Open – Men's singles was an event of the 1971 Monte Carlo Open tennis tournament. Željko Franulović was the defending champion but did not compete in this edition. Third-seeded Ilie Năstase won the singles title by defeating first-seeded Tom Okker 3–6, 8–6, 6–1, 6–1 in the final.

Seeds
• # Tom Okker (final)

• # 🇬🇧 Roger Taylor (semifinals)

• # 🇷🇴 Ilie Năstase (champion)

• # Jan Kodeš (first round)

• # 🇷🇴 Ion Țiriac (semifinals)

• # 🇪🇸 Manuel Orantes (second round)

• # 🇫🇷 Pierre Barthès (quarterfinals)

• # 🇪🇬 Ismail El Shafei (first round)