See main article: 2012 Sony Ericsson Open.
Agnieszka Radwańska defeated Maria Sharapova in the final, 7–5, 6–4 to win the women's singles tennis title at the 2012 Miami Open. It was her second Premier Mandatory title and first Miami Masters title. Radwańska did not drop a set during the tournament.
Victoria Azarenka was the defending champion, but lost to Marion Bartoli in the quarterfinals, ending Azarenka's 26-match winning streak to start the 2012 season.
This tournament also marked the first WTA Tour main draw appearance of two-time major champion and future world No. 1, Garbiñe Muguruza, where she made the fourth round before losing to Radwańska.
All seeds received a bye into the second round.
See also: 1 and 1. 
Victoria Azarenka (quarterfinals)
See also: 2 and 8. 
Maria Sharapova (final)
See also: 3 and 3. 
Petra Kvitová (second round)
See also: 4 and 6. Caroline Wozniacki (semifinals)
See also: 5 and 4. 
Agnieszka Radwańska (champion)
See also: 6 and 5. 
Samantha Stosur (fourth round)
See also: 7 and 2. 
Marion Bartoli (semifinals)
See also: 8 and 7. 
Li Na (quarterfinals)
See also: 9 and 4. Vera Zvonareva (second round)
See also: 10 and 5. 
Serena Williams (quarterfinals)
See also: 11 and 2. 
Francesca Schiavone (second round)
See also: 12 and 7. Sabine Lisicki (fourth round)
See also: 13 and 8. 
Jelena Janković (second round)
See also: 14 and 6. Julia Görges (second round)
See also: 15 and 3. Ana Ivanovic (fourth round)
See also: 16 and 1. 
Dominika Cibulková (fourth round)
See also: 17 and 7. Peng Shuai (third round)
See also: 18 and 1. Angelique Kerber (second round)
See also: 19 and 8. Anastasia Pavlyuchenkova (second round)
See also: 20 and 3. Daniela Hantuchová (third round)
See also: 21 and 5. Roberta Vinci (third round)
See also: 22 and 2. Maria Kirilenko (fourth round)
See also: 23 and 6. 
Yanina Wickmayer (fourth round)
See also: 24 and 4. Flavia Pennetta (third round)
See also: 25 and 5. 
Anabel Medina Garrigues (second round)
See also: 26 and 7. Svetlana Kuznetsova (second round)
See also: 27 and 1. Lucie Šafářová (second round)
See also: 28 and 3. Monica Niculescu (second round)
See also: 29 and 6. Petra Cetkovská (third round)
See also: 30 and 8. Sara Errani (second round)
See also: 31 and 4. 
Kaia Kanepi (second round)
See also: 32 and 2. Nadia Petrova (second round)
See also: 1 and 1. 
Kateryna Bondarenko (qualified)
See also: 2 and 2. 
Anne Keothavong (first round)
See also: 3 and 3. Hsieh Su-wei (qualifying competition)
See also: 4 and 4. Vera Dushevina (qualified)
See also: 5 and 5. Varvara Lepchenko (qualifying competition)
See also: 6 and 6. Alexandra Panova (first round)
See also: 7 and 7. Urszula Radwańska (qualified)
See also: 8 and 8. Olga Govortsova (first round)
See also: 9 and 9. Stéphanie Foretz Gacon (qualified)
See also: 10 and 10. Sloane Stephens (qualified)
See also: 11 and 11. 
Stéphanie Dubois (first round)
See also: 12 and 12. 
Mandy Minella (qualifying competition)
See also: 13 and 6. 
Patricia Mayr-Achleitner (first round)
See also: 14 and 9. 
Edina Gallovits-Hall (first round)
See also: 15 and 3. Nina Bratchikova (first round)
See also: 16 and 2. Arantxa Rus (qualifying competition)
See also: 17 and 12. Jamie Hampton (qualified)
See also: 18 and 10. Irina Falconi (first round)
See also: 19 and 8. Anastasia Rodionova (qualifying competition)
See also: 20 and 7. Chang Kai-chen (first round, retired)
See also: 21 and 1. Lara Arruabarrena Vecino (first round)
See also: 22 and 11. Eva Birnerová (qualified)
See also: 23 and 4. Alla Kudryavtseva (first round)
See also: 24 and 5. Valeria Savinykh (qualified)
Kateryna Bondarenko
Misaki Doi Alizé Cornet Vera Dushevina Valeria Savinykh
Melinda Czink Urszula Radwańska Madison Keys Stéphanie Foretz Gacon Sloane Stephens Eva Birnerová Jamie Hampton