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.