Language, Study Guide, Children's Book Series Beginning with O
- Curious George
- Ohoka Echizen
- Ojamajo
- Ojarumaru
- Okami Shojo to Kuro Oji
- Okasan to Issho
- Olympic
- Omae Umasodana
- Omoi, Omoware, Furi, Furare
- Omoide no Marnie (When Marnie Was There)
- Omotesandou Kouko Gassyobu!
- One Piece
- Onegai My Melody
- Online Game
- Only Yesterday
- Ookami kodomo no Ame to Yuki (Wolf Children)
- Ookami-san Series
- orange
- Orange Page
- Ore monogatari!!
- Ore no Imoto ga Kon nani Kawaii wake ga nai
- Orient
- Orix Buffaloes
- Osama Game
- Osen
- Oshiri Tantei
- Osomatsu-san
- Otherside PIcnic