See main article: 2003 Hamburg Masters.
Guillermo Coria defeated Agustín Calleri in the final, 6–3, 6–4, 6–4 to win the singles tennis title at the 2003 Hamburg European Open.
Roger Federer was the defending champion, but lost in the third round to Mark Philippoussis.
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated.