O
- Octavia Sperati
- Silje, Bodil, Gyri, Trine, Tone
- Ongaku Gatas
- Onyanko Club
- OOIOO
- Yoshimi P-We, Kayan, Aya, Ai
- ORESKABAND
- Ikasu, Tae-san, Leader, Saki, Moriko, Tomi
- The Organ
- Katie Sketch, Jenny Smythe, Shelby Stocks, Shmoo Ritchie, Debra Cohen
- Osaka Performance Doll
- Atsuko Inaba, Ayano Furutani, Yukiko Takeuchi, Miho Ueda, Kumiko Nakano
- Out of Eden
- Lisa Kimmey, Andrea Kimmey-Baca, Danielle Kimmey
Read more about this topic: List Of All-female Bands