Juan Carlos Ferrero defeated Martin Verkerk in the final, 6–1, 6–3, 6–2 to win the men's singles tennis title at the 2003 French Open. It was his first and only major singles title. Albert Costa was the defending champion, but lost in the semifinals to Ferrero in a rematch of the previous year's final. This was the last major where future world No. 1 Roger Federer lost in the first round.

Seeds

• 🇦🇺 Lleyton Hewitt (third round) • 🇺🇸 Andre Agassi (quarterfinals) • 🇪🇸 Juan Carlos Ferrero (champion) • 🇪🇸 Carlos Moyà (quarterfinals) • Roger Federer (first round) • 🇺🇸 Andy Roddick (first round) • 🇦🇷 Guillermo Coria (semifinals) • 🇦🇷 David Nalbandian (second round) • 🇪🇸 Albert Costa (semifinals) • 🇹🇭 Paradorn Srichaphan (first round) • 🇩🇪 Rainer Schüttler (fourth round) • Sjeng Schalken (third round, retired because of a stomach ache) • 🇨🇿 Jiří Novák (fourth round) • 🇫🇷 Sébastien Grosjean (second round) • 🇧🇷 Gustavo Kuerten (fourth round) • 🇪🇸 Àlex Corretja (first round) • 🇷🇺 Yevgeny Kafelnikov (second round) • 🇦🇷 Agustín Calleri (first round) • Fernando González (quarterfinals) • 🇪🇸 Félix Mantilla (fourth round) • 🇦🇷 Gastón Gaudio (third round) • Wayne Ferreira (third round, retired because of a groin injury) • 🇲🇦 Younes El Aynaoui (third round) • 🇺🇸 James Blake (second round) • 🇬🇧 Tim Henman (third round) • 🇧🇪 Xavier Malisse (third round) • 🇷🇺 Mikhail Youzhny (second round) • 🇪🇸 Tommy Robredo (quarterfinals) • 🇺🇸 Vince Spadea (third round) • 🇫🇮 Jarkko Nieminen (fourth round) • 🇦🇷 Juan Ignacio Chela (third round) • 🇫🇷 Arnaud Clément (fourth round)

Qualifying

Draw

Finals

Top half

Section 1

Section 2

Section 3

Section 4

Bottom half

Section 5

Section 6

Section 7

Section 8