Calendar Series Beginning with O
- [Oshi no ko]
- Curious George
- My Next Life as a Villainess: All Routes Lead to Doom!
- Obey Me!
- Odekake Kozame
- Ojarumaru
- Ojisan Ha Kawai I Mono Ga Osuki.
- Okami to Koshinryo (Wolf and Spice)
- Okasan to Issho
- Omoide no Marnie (When Marnie Was There)
- One Piece
- Onegai My Melody
- Onimai: I'm Now Your Sister!
- Online Game
- Orange Page
- Ore no Imoto ga Kon nani Kawaii wake ga nai
- Ore no nonai sentakushi ga gakuen Love comedy wo Zenryoku de Jyama Shiteiru
- Ore, Tsushima
- Orix Buffaloes
- Osama Ranking
- Oshiri Tantei
- Osomatsu-san
- Ossan's Love
- Otoko wa Tsuraiyo
- Overlord
- Seraph of the End
- The Royal Tutor (Oshitsu Kyoshi Haine)