2005 Grand Prix de Tennis de Lyon – Singles

Robin Söderling was the defending champion, but did not participate this year.

Andy Roddick won the tournament, beating Gaël Monfils 6–3, 6–2 in the final.

Seeds
• # 🇺🇸 Andy Roddick (champion)

• # 🇦🇷 Mariano Puerta (first round)

• # 🇦🇷 Gastón Gaudio (second round)

• # Ivan Ljubičić (first round)

• # 🇪🇸 Tommy Robredo (second round)

• # 🇪🇸 David Ferrer (first round)

• # Mario Ančić (quarterfinals)

• # 🇺🇸 Robby Ginepri (first round, retired due to a stomach virus)