The 2003 Hamburg Masters was a men's tennis tournament played on outdoor clay courts. It was the 97th edition of the Hamburg Masters and was part of the Tennis Masters Series of the 2003 ATP Tour. It took place at the Am Rothenbaum in Hamburg, Germany from 12 May through 18 May 2003.
The singles field was headlined by new ATP No. 1, Scottsdale, Indian Wells winner and Masters Cup defending champion Lleyton Hewitt, Buenos Aires, Barcelona champion, Miami runner-up and Monte Carlo semifinalist Carlos Moyá and Marseille, Dubai, Munich winner and recent Rome finalist Roger Federer. Other top seeds competing were Memphis and Houston finalist Andy Roddick, 2002 French Open champion Albert Costa, Jiří Novák, Paradorn Srichaphan and David Nalbandian. Young Rafael Nadal at 16 defeated world number 4 Moya in 2 sets.
For the first time in a Tennis Masters Series tournament all four semifinalists were from the same country. The Argentine semifinalists were Guillermo Coria, Agustín Calleri, Gastón Gaudio and David Nalbandian.
See main article: 2003 Hamburg Masters – Singles. 
Guillermo Coria defeated Agustín Calleri 6–3, 6–4, 6–4
See main article: 2003 Hamburg Masters – Doubles. Mark Knowles / 
Daniel Nestor defeated 
Mahesh Bhupathi / 
Max Mirnyi 6–4, 7–6(12–10)