| Champ: |  Serena Williams |
| Runner: |  Maria Sharapova |
| Score: | 4–6, 6–3, 6–0 |
| Draw: | 96 |
| Seeds: | 32 |
| Main Name: | Miami Masters |
| Before Name: | Sony Ericsson Open – Women's singles |
| After Name: | Sony Open Tennis – Women's singles |
See main article: 2013 Sony Open Tennis.
Serena Williams defeated Maria Sharapova in the final, 4–6, 6–3, 6–0 to win the women's singles tennis title at the 2013 Miami Open. It was her record sixth Miami Open title, and Sharapova's fifth runner-up finish without winning the title.
Agnieszka Radwańska was the defending champion, but lost in the semifinals to Williams.
All seeds receive a bye into the second round.