2018 St. Petersburg Ladies' Trophy – Singles

Kristina Mladenovic was the defending champion, but lost in the final to unseeded Petra Kvitová, 1–6, 2–6. As a result, Kvitová became the first left-handed player to win a singles title in Russia. She was also the first wildcard to win the event.

Seeds
The top four seeds received a bye into the second round. • # Caroline Wozniacki (quarterfinals)

• # Jeļena Ostapenko (quarterfinals)

• # 🇫🇷 Caroline Garcia (second round)

• # 🇫🇷 Kristina Mladenovic (final)

• # 🇩🇪 Julia Görges (semifinals)

• # 🇷🇺 Anastasia Pavlyuchenkova (first round)

• # 🇷🇺 Elena Vesnina (first round)

• # 🇷🇺 Daria Kasatkina (semifinals)

Seeds
• # 🇨🇿 Kristýna Plíšková (second round)

• # 🇷🇺 Natalia Vikhlyantseva (qualifying competition)

• # 🇬🇧 Heather Watson (first round)

• # 🇧🇪 Kirsten Flipkens (first round)

• # 🇫🇷 Océane Dodin (second round)

• # 🇪🇸 Lara Arruabarrena (first round)

• # 🇷🇺 Ekaterina Alexandrova (first round)

• # 🇩🇪 Andrea Petkovic (qualifying competition, lucky loser)

Qualifiers
• # 🇨🇿 Tereza Martincová

• # 🇸🇰 Viktória Kužmová

• # 🇮🇹 Roberta Vinci

• # 🇷🇺 Elena Rybakina

Lucky loser
• # 🇩🇪 Andrea Petkovic