Classical Music Series Beginning with O
- Oka-san Musume wo Yameteiidesuka?
- Okami Shojo to Kuro Oji
- Okasan to Issho
- Omoide no Marnie (When Marnie Was There)
- Omotesandou Kouko Gassyobu!
- One Piece
- Onna Joshu Naotora
- Ookami kodomo no Ame to Yuki (Wolf Children)
- Osama Ranking
- Osomatsu-san
- Osozaki no Himawari
- Ossan's Love
- Otaku ni Koi wa Muzukashii