2003 NASDAQ-100 Open – Women's singles

Defending champion Serena Williams defeated Jennifer Capriati in a rematch of the previous year's final, 4–6, 6–4, 6–1 to win the women's singles tennis title at the 2003 Miami Open.

Seeds
All seeds received a bye into the second round.


 * 1) 🇺🇸 Serena Williams (champion)
 * 2) 🇺🇸 Venus Williams (fourth round)
 * 3) 🇧🇪 Kim Clijsters (semifinals)
 * 4) 🇧🇪 Justine Henin-Hardenne (quarterfinals)
 * 5) 🇸🇰 Daniela Hantuchová (second round)
 * 6) 🇺🇸 Jennifer Capriati (final)
 * 7) 🇺🇸 Lindsay Davenport (fourth round, retired)
 * 8) 🇫🇷 Amélie Mauresmo (fourth round)
 * 9)  Jelena Dokić (quarterfinals)
 * 10) 🇺🇸 Monica Seles (withdrew)
 * 11) 🇷🇺 Anastasia Myskina (second round)
 * 12) 🇺🇸 Chanda Rubin (semifinals)
 * 13) 🇧🇬 Magdalena Maleeva (third round)
 * 14)  Eleni Daniilidou (third round)
 * 15) 🇮🇱 Anna Pistolesi (fourth round)
 * 16) 🇷🇺 Elena Bovina (second round)
 * 17) 🇯🇵 Ai Sugiyama (third round)
 * 18)  Amanda Coetzer (second round)
 * 19) 🇷🇺 Elena Dementieva (second round)
 * 20) 🇮🇹 Silvia Farina Elia (third round)
 * 21) 🇫🇷 Nathalie Dechy (third round)
 * 22) 🇺🇸 Lisa Raymond (third round)
 * 23) 🇺🇸 Meghann Shaughnessy (quarterfinals)
 * 24) 🇺🇸 Alexandra Stevenson (second round)
 * 25) 🇷🇺 Tatiana Panova (third round)
 * 26) 🇦🇷 Clarisa Fernández (third round)
 * 27) 🇦🇷 Paola Suárez (third round)
 * 28) 🇷🇺 Elena Likhovtseva (third round)
 * 29)  Iva Majoli (second round)
 * 30) 🇹🇭 Tamarine Tanasugarn (third round)
 * 31) 🇺🇸 Laura Granville (third round)
 * 32)  Marie-Gayanay Mikaelian (second round)

Qualifying seeds
• # 🇭🇺 Petra Mandula (first round)

• # 🇪🇸 Marta Marrero (qualified)

• # 🇦🇺 Evie Dominikovic (qualifying competition, lucky loser)

• # 🇸🇪 Åsa Svensson (qualified)

• # 🇪🇸 María Sánchez Lorenzo (qualified)

• # Dally Randriantefy (first round)

• # Rossana de los Ríos (first round)

• # 🇫🇷 Marion Bartoli (qualified)

• # 🇩🇪 Marlene Weingärtner (qualified)

• # Jelena Kostanić (qualifying competition)

• # 🇺🇸 Ashley Harkleroad (qualifying competition)

• # 🇷🇺 Evgenia Kulikovskaya (first round)

• # 🇫🇷 Stéphanie Cohen-Aloro (first round)

• # 🇯🇵 Saori Obata (first round)

• # 🇸🇰 Martina Suchá (first round)

• # 🇨🇿 Libuše Průšová (first round)

• # 🇺🇸 Lindsay Lee-Waters (qualifying competition)

• # 🇺🇸 Ansley Cargill (qualifying competition)

• # 🇷🇺 Nadia Petrova (qualifying competition)

• # 🇺🇸 Samantha Reeves (first round)

• # 🇻🇪 Milagros Sequera (first round)

• # 🇸🇰 Ľubomíra Kurhajcová (qualifying competition)

• # 🇨🇦 Maureen Drake (qualifying competition)

• # Wynne Prakusya (first round)

Qualifiers
• # 🇺🇸 Mashona Washington

• # 🇪🇸 Marta Marrero

• # 🇱🇺 Claudine Schaul

• # 🇸🇪 Åsa Svensson

• # 🇪🇸 María Sánchez Lorenzo

• # Jelena Janković

• # 🇷🇺 Vera Dushevina

• # 🇫🇷 Marion Bartoli

• # 🇩🇪 Marlene Weingärtner

• # 🇺🇦 Tatiana Perebiynis

• # 🇷🇺 Anastasia Rodionova

• # 🇨🇦 Marie-Ève Pelletier

Lucky loser

 * 1) 🇦🇺 Evie Dominikovic