Toys & Kids Series Beginning with O
- [Oshi no ko]
- Curious George
- My Next Life as a Villainess: All Routes Lead to Doom!
- Obey Me!
- OCTOPATH TRAVELER
- Oda Shinamon Nobunaga
- Odd Taxi
- Odoru Daisosasen Series
- Ohoka Echizen
- Oi! Hanimaru
- Ojamajo
- Ojarumaru
- Okami to Koshinryo (Wolf and Spice)
- Okasan to Issho
- Okitegami Kyoko Series
- Omae Umasodana
- Omoi, Omoware, Furi, Furare
- Omoide no Marnie (When Marnie Was There)
- One Piece
- One Punch Man
- Onegai My Melody
- ONGEKI
- Onichan Dakedo Ai Sae Areba Kankeinaiyone
- Onimai: I'm Now Your Sister!
- Online Game
- Only Yesterday
- Ookami kodomo no Ame to Yuki (Wolf Children)
- Ookami-san Series
- Opanchu Usagi
- Orange Page
- Ore no Imoto ga Kon nani Kawaii wake ga nai
- Orient
- Orix Buffaloes
- Osen
- Oshi ga Budokan Ittekuretara Shinu
- Oshiri Tantei
- Osomatsu-san
- Ossan's Love
- Otoca Doll
- Otogi Jushi Akazukin
- Otome continue
- otona MUSE
- Otona No Nurie
- Ouran Koko Host Club
- Outlandar
- Overlord
- Oyasumi Punpun
- Seraph of the End
- The Royal Tutor (Oshitsu Kyoshi Haine)