2018 Oracle Challenger Series – Chicago – Women's singles

This was the first edition of the tournament.

Petra Martić won the title, defeating Mona Barthel in the final, 6–4, 6–1.

Seeds
• # 🇺🇸 Danielle Collins (second round)

• # Petra Martić (champion)

• # 🇰🇿 Zarina Diyas (second round)

• # 🇩🇪 Tatjana Maria (semifinals)

• # 🇫🇷 Pauline Parmentier (first round)

• # 🇺🇸 Sachia Vickery (semifinals, withdrew)

• # 🇷🇺 Evgeniya Rodina (first round)

• # 🇸🇪 Johanna Larsson (second round)

Seeds
• # 🇺🇸 Kristie Ahn (qualified)

• # 🇺🇸 Irina Falconi (qualified)

• # 🇺🇸 Jamie Loeb (qualified)

• # 🇨🇿 Marie Bouzková (first round, retired)

• # 🇰🇿 Elena Rybakina (qualifying competition)

• # 🇧🇬 Sesil Karatantcheva (qualified)

• # 🇺🇸 Ashley Kratzer (qualifying competition)

• # 🇮🇳 Karman Thandi (first round)

• # 🇨🇦 Françoise Abanda (qualified)

• # 🇺🇸 Asia Muhammad (qualifying competition)

• # 🇨🇿 Tereza Martincová (qualifying competition)

• # 🇺🇸 Maria Sanchez (first round)

Qualifiers
• # 🇺🇸 Kristie Ahn

• # 🇺🇸 Irina Falconi

• # 🇺🇸 Jamie Loeb

• # 🇺🇸 Robin Anderson

• # 🇨🇦 Françoise Abanda

• # 🇧🇬 Sesil Karatantcheva