1991 Philips Austrian Open – Singles

Horacio de la Peña was the defending champion, but lost in the third round to Francisco Clavet.

Karel Nováček won the title by defeating Magnus Gustafsson 7–6(7–2), 7–6(7–4), 6–2 in the final.

Seeds
All seeds received a bye to the second round. • # 🇪🇸 Sergi Bruguera (second round)

• # 🇪🇸 Emilio Sánchez (quarterfinals)

• # Karel Nováček (champion)

• # 🇸🇪 Magnus Gustafsson (final)

• # 🇦🇹 Horst Skoff (quarterfinals)

• # 🇦🇷 Alberto Mancini (third round)

• # 🇪🇸 Francisco Clavet (semifinals)

• # 🇦🇷 Martín Jaite (semifinals)

• # 🇦🇷 Horacio de la Peña (third round)

• # 🇸🇪 Christian Bergström (third round)

• # 🇪🇸 Javier Sánchez (third round)

• # 🇫🇷 Thierry Champion (quarterfinals)

• # Marián Vajda (third round)

• # 🇦🇹 Thomas Muster (third round)

• # Marcelo Filippini (second round)

• # 🇫🇷 Cédric Pioline (second round)