1991 ATP German Open – Singles

Karel Nováček defeated Magnus Gustafsson in the final, 6–3, 6–3, 5–7, 0–6, 6–1 to win the singles tennis title at the 1991 Hamburg European Open.

Juan Aguilera was the defending champion, but lost in the first round to Jordi Arrese.

Seeds
• # 🇸🇪 Stefan Edberg (Quarterfinal)

• # Ivan Lendl (second round)

• # 🇺🇸 Pete Sampras (third round)

• # Goran Ivanišević (Quarterfinal, retired)

• # 🇪🇸 Sergi Bruguera (third round)

• # 🇺🇸 Jim Courier (second round)

• # 🇸🇪 Jonas Svensson (second round)

• # 🇪🇸 Emilio Sánchez (second round)

• # 🇩🇪 Michael Stich (semifinal)

• # Andrei Cherkasov (second round)

• # 🇪🇨 Andrés Gómez (first round)

• # Andrei Chesnokov (first round)

• # Karel Nováček (champion)

• # Alexander Volkov (third round)

• # 🇦🇷 Guillermo Pérez Roldán (withdrew)

• # Marc Rosset (first round)