Music Series Beginning with O
- [Oshi no ko]
- Curious George
- Occultic;Nine
- Ochoyan
- Octave
- Oda Nobuna no Yabou
- Odoru Daisosasen Series
- Oedo Rocket
- Oh! My Girl!!
- Oh, My Dad!!
- Oh-oku ( Danjo Gyakuten)
- Oh-oku / Ooku
- Ohisama
- Ohitori sama
- Ohoka Echizen
- Oishi Propose
- Oishii Coffee no Irekata
- Oishii Gohan
- Ojamajo
- Ojiisan Sensei
- Ojisan Ha Kawai I Mono Ga Osuki.
- Oka-san Musume wo Yameteiidesuka?
- Okaeri Mone
- Okami Shojo to Kuro Oji
- Okami to Koshinryo (Wolf and Spice)
- Okasan to Issho
- Okiku Furikabutte
- Okitegami Kyoko Series
- Okoshiyasu Chitose Chan
- Ol Nippon
- Omae wa mada Gunma wo shiranai
- Omiyasan
- Omo ni Naiteimasu
- Omoi, Omoware, Furi, Furare
- Omoide no Marnie (When Marnie Was There)
- Omotesandou Kouko Gassyobu!
- Omukaedesu.
- One Piece
- One Room
- Onegai My Melody
- Ongaku to Hito
- Ongaku-shi ga Kakanai Jpop Hihyo
- Onihei Hankacho
- Onimai: I'm Now Your Sister!
- Oniyome Nikki
- Online Game
- Only Yesterday
- Onna Joshu Naotora
- Onna Keiji Mizuki
- Onna Kudoki Meshi
- Onna wa sore wo yurusanai
- Onosaka, Konishi no O+K(OTASUKE)
- Onsen he Go!
- Onsen Yosei Hakone-Chan
- Ookami kodomo no Ame to Yuki (Wolf Children)
- orange
- Ore Ga Sukina No Ha Imotodakedo Imoto Janai
- Ore monogatari!!
- Ore no Hanashi wa Nagai
- Ore no Imoto ga Kon nani Kawaii wake ga nai
- Ore no Kanojo to Osananajimi ga Shuraba Sugiru
- Ore no Koto Sukidesho
- Ore no nonai sentakushi ga gakuen Love comedy wo Zenryoku de Jyama Shiteiru
- Ore no Sora Series
- Ore o Suki nano wa Omae dake kayo
- Ore, Twintail ni Narimasu.
- Orenchi no Furo Jijyo
- Ori Sta
- Orix Buffaloes
- Orthros no Inu
- Orustak Pictures
- Osake wa Fufu ni Nattekara
- Osama Game
- Osama Ranking
- Osen
- Osomatsu-san
- Osozaki no Himawari
- Ossan's Love
- Otakara File
- Otaku Elf
- Otaku ni Koi wa Muzukashii
- Otenki One-san
- Otherside PIcnic
- Otoca Doll
- Otoko no Kosodate
- Otoko wa Tsuraiyo
- Otokomeshi
- Otokotachi no Yamato
- Otome-San
- Otona Joshi
- Otona Koukou
- Otona no Kagaku Magazine
- Otosan to Yobasete
- Ougon no Buta
- Ougon no Gt
- OUR HOUSE
- Ouran Koko Host Club
- Ouroboros
- Outbreak Company
- Over 30