Hobby, Travel, Sports Series Beginning with O
- Curious George
- Ochoyan
- Oh-oku ( Danjo Gyakuten)
- Oishinbo
- Ojamajo
- Ojarumaru
- Okami to Koshinryo (Wolf and Spice)
- Okasan to Issho
- Okiku Furikabutte
- Olympic
- Omae Umasodana
- Omoide no Marnie (When Marnie Was There)
- Omotesandou Kouko Gassyobu!
- One Piece
- One Punch Man
- Onegai My Melody
- Onegai Teacher (Please Teacher!)
- Onihei Hankacho
- Onimusha
- Online Game
- Only Mercedes
- Only Yesterday
- Onsen Musume
- Ooi! Tombo
- Ookami kodomo no Ame to Yuki (Wolf Children)
- Ookami-san Series
- 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
- Orix Buffaloes
- Oshiri Tantei
- Osomatsu-san
- Otoko wa Tsuraiyo
- Otokomeshi
- Otona Anime
- Otona no Kagaku Magazine
- Otona No Nurie
- Otona no Oshare Techo
- Outlandar