2020 St. Petersburg Ladies' Trophy – Singles

Kiki Bertens was the defending champion and successfully defended her title, defeating Elena Rybakina in the final, 6–1, 6–3. This would be Bertens' final WTA Tour singles title before her retirement in July 2021.

Seeds
• # Belinda Bencic (quarterfinals)

• # Kiki Bertens (champion)

• # 🇨🇿 Petra Kvitová (quarterfinals, withdrew)

• # 🇬🇧 Johanna Konta (second round)

• # 🇨🇿 Markéta Vondroušová (first round)

• # Maria Sakkari (semifinals)

• # Donna Vekić (second round)

• # 🇰🇿 Elena Rybakina (final)

Seeds
• # 🇫🇷 Fiona Ferro (qualifying competition, lucky loser)

• # 🇫🇷 Alizé Cornet (qualified)

• # 🇷🇺 Vitalia Diatchenko (qualified)

• # 🇺🇸 Kristie Ahn (qualified)

• # 🇭🇺 Tímea Babos (qualifying competition)

• # 🇷🇺 Anastasia Potapova (qualified)

• # 🇷🇺 Varvara Gracheva (first round)

• # 🇷🇺 Margarita Gasparyan (first round)

• # 🇷🇺 Liudmila Samsonova (qualified)

• # 🇷🇺 Natalia Vikhlyantseva (qualifying competition)

• # 🇫🇷 Pauline Parmentier (qualifying competition)

• # 🇨🇿 Tereza Martincová (qualifying competition)

Qualifiers
• # 🇫🇷 Océane Dodin

• # 🇫🇷 Alizé Cornet

• # 🇷🇺 Vitalia Diatchenko

• # 🇺🇸 Kristie Ahn

• # 🇷🇺 Liudmila Samsonova

• # 🇷🇺 Anastasia Potapova

Lucky loser
• # 🇫🇷 Fiona Ferro