The 2003 Tennis Masters Cup was a tennis tournament played on outdoor hard courts. It was the 34th edition of the year-end singles championships and the 29th edition of the year-end doubles championships, and was part of the 2003 ATP Tour. It took place at the Westside Tennis Club in Houston, Texas in the United States from November 8 through November 16, 2003.
Roger Federer defeated Andre Agassi 6–3, 6–0, 6–4
- It was Federer's 9th title of the year and the 17th of his career. It was his 1st career year-end championships title.
Bob Bryan / Mike Bryan defeated Michaël Llodra / Fabrice Santoro 6–7(6–8), 6–3, 3–6, 7–6(7–3), 6–4
- It was Bob Bryan's 5th title of the year and the 14th of his career. It was Mike Bryan's 5th title of the year and the 16th of his career.
|Masters Grand Prix
ATP Tour World Championships
Tennis Masters Cup
ATP World Tour Finals