2015 Western & Southern Open – Women's singles

Defending champion Serena Williams defeated Simona Halep in the final, 6–3, 7–6(7–5) to win the women's singles tennis title at the 2015 Cincinnati Masters.

Seeds
The top eight seeds received a bye into the second round.

🇺🇸 Serena Williams (champion) 🇷🇺 Maria Sharapova (withdrew because of a right leg injury) 🇷🇴 Simona Halep (final) 🇨🇿 Petra Kvitová (second round) Caroline Wozniacki (second round) 🇷🇸 Ana Ivanovic (quarterfinals) 🇨🇿 Lucie Šafářová (quarterfinals) 🇨🇿 Karolína Plíšková (third round) 🇪🇸 Garbiñe Muguruza (first round) 🇪🇸 Carla Suárez Navarro (first round) 🇩🇪 Angelique Kerber (first round) Timea Bacsinszky (first round) 🇵🇱 Agnieszka Radwańska (first round) 🇺🇦 Elina Svitolina (semifinals) 🇩🇪 Andrea Petkovic (third round) 🇮🇹 Sara Errani (first round)

Seeds
• # 🇷🇴 Monica Niculescu (first round)

• # 🇸🇰 Anna Karolína Schmiedlová (qualified)

• # 🇸🇪 Johanna Larsson (first round)

• # 🇸🇰 Magdaléna Rybáriková (first round)

• # 🇷🇴 Alexandra Dulgheru (first round)

• # Mirjana Lučić-Baroni (qualifying competition, lucky loser)

• # 🇧🇪 Alison Van Uytvanck (withdrew)

• # 🇩🇪 Annika Beck (first round)

• # 🇩🇪 Carina Witthöft (first round)

• # 🇨🇿 Lucie Hradecká (qualified)

• # 🇺🇸 Christina McHale (qualified)

• # 🇩🇪 Mona Barthel (qualified)

• # 🇩🇪 Julia Görges (qualified)

• # 🇦🇺 Casey Dellacqua (qualified)

• # 🇷🇸 Aleksandra Krunić (first round)

• # 🇩🇪 Tatjana Maria (qualifying competition)

• # 🇬🇧 Heather Watson (first round)

• # Polona Hercog (qualifying competition)

• # 🇪🇸 Lara Arruabarrena (first round)

• # 🇯🇵 Kurumi Nara (qualifying competition, retired)

• # 🇷🇴 Andreea Mitu (first round)

• # 🇺🇸 Irina Falconi (qualifying competition)

• # 🇦🇺 Jarmila Gajdošová (first round)

• # 🇧🇾 Olga Govortsova (qualifying competition)

• # 🇰🇿 Yulia Putintseva (qualified)

Qualifiers
• # 🇭🇺 Tímea Babos

• # 🇸🇰 Anna Karolína Schmiedlová

• # Ana Konjuh

• # 🇩🇪 Julia Görges

• # 🇺🇦 Kateryna Bondarenko

• # 🇦🇺 Casey Dellacqua

• # 🇰🇿 Yulia Putintseva

• # 🇺🇸 Lauren Davis

• # 🇰🇿 Yaroslava Shvedova

• # 🇨🇿 Lucie Hradecká

• # 🇺🇸 Christina McHale

• # 🇩🇪 Mona Barthel

Lucky loser

 * 1)  Mirjana Lučić-Baroni