2018 Miami Open – Women's singles

Sloane Stephens defeated Jeļena Ostapenko in the final, 7–6(7–5), 6–1 to win the women's singles tennis title at the 2018 Miami Open. It was Stephens' sixth career singles title, first Premier Mandatory title, and first title since winning the US Open back in September. By virtue of her victory, Stephens also made her debut in the Top 10, at No. 9.

Johanna Konta was the defending champion, but lost in the fourth round to Venus Williams.

Danielle Collins became the first qualifier in Miami Open history to reach the semifinals.

Seeds
All seeds received a bye into the second round. • 🇷🇴 Simona Halep (third round)

• Caroline Wozniacki (second round)

• 🇪🇸 Garbiñe Muguruza (fourth round)

• 🇺🇦 Elina Svitolina (quarterfinals)

• 🇨🇿 Karolína Plíšková (quarterfinals)

•  Jeļena Ostapenko (final)

• 🇫🇷 Caroline Garcia (second round)

• 🇺🇸 Venus Williams (quarterfinals)

• 🇨🇿 Petra Kvitová (fourth round)

• 🇩🇪 Angelique Kerber (quarterfinals)

• 🇬🇧 Johanna Konta (fourth round)

• 🇩🇪 Julia Görges (second round)

• 🇺🇸 Sloane Stephens (champion)

• 🇺🇸 Madison Keys (second round, retired)

• 🇫🇷 Kristina Mladenovic (second round)

• 🇺🇸 CoCo Vandeweghe (second round)

• 🇸🇰 Magdaléna Rybáriková (second round)

• 🇷🇺 Svetlana Kuznetsova (second round)

• 🇷🇺 Daria Kasatkina (second round)

•  Anastasija Sevastova (third round)

• 🇦🇺 Ashleigh Barty (fourth round)

• 🇧🇪 Elise Mertens (third round)

• 🇷🇺 Anastasia Pavlyuchenkova (third round)

• 🇷🇺 Elena Vesnina (second round)

• 🇨🇿 Barbora Strýcová (second round)

• 🇦🇺 Daria Gavrilova (third round)

• 🇪🇸 Carla Suárez Navarro (second round)

• 🇪🇪 Anett Kontaveit (second round)

•  Kiki Bertens (third round)

• 🇵🇱 Agnieszka Radwańska (fourth round)

• 🇨🇳 Zhang Shuai (second round)

• 🇷🇴 Sorana Cîrstea (second round)

Seeds
• # 🇷🇴 Monica Niculescu (qualified)

• # Polona Hercog (qualified)

• # 🇷🇺 Natalia Vikhlyantseva (qualified)

• # 🇮🇹 Sara Errani (first round)

• # 🇫🇷 Pauline Parmentier (first round)

• # 🇨🇳 Duan Yingying (first round, retired)

• # 🇫🇷 Océane Dodin (qualifying competition, retired, lucky loser)

• # 🇯🇵 Kurumi Nara (first round)

• # 🇸🇰 Jana Čepelová (qualifying competition)

• # 🇺🇸 Sachia Vickery (first round)

• # 🇺🇸 Taylor Townsend (first round)

• # 🇺🇸 Sofia Kenin (qualified)

• # 🇩🇪 Andrea Petkovic (qualified)

• # 🇺🇸 Alison Riske (qualified)

• # Viktorija Golubic (qualified)

• # 🇺🇸 Kristie Ahn (first round)

• # 🇪🇸 Sara Sorribes Tormo (first round)

• # 🇷🇺 Evgeniya Rodina (first round)

• # Jana Fett (first round, retired)

• # 🇨🇴 Mariana Duque Mariño (first round)

• # 🇧🇪 Yanina Wickmayer (qualifying competition)

• # 🇨🇦 Eugenie Bouchard (qualifying competition)

• # 🇺🇸 Danielle Collins (qualified)

• # 🇺🇸 Nicole Gibbs (qualifying competition)

Qualifiers
• # 🇷🇴 Monica Niculescu

• # Polona Hercog

• # 🇷🇺 Natalia Vikhlyantseva

• # Stefanie Vögele

• # 🇸🇪 Rebecca Peterson

• # 🇨🇳 Wang Yafan

• # 🇺🇸 Alison Riske

• # 🇩🇪 Andrea Petkovic

• # 🇺🇸 Danielle Collins

• # Viktorija Golubic

• # 🇬🇧 Katie Boulter

• # 🇺🇸 Sofia Kenin

Lucky loser
• # 🇫🇷 Océane Dodin