Books Series Beginning with O
- Ore monogatari!!
- 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, Tsushima
- Ore, Twintail ni Narimasu.
- Orenchi no Furo Jijyo
- Oretachi Majikou Destroy
- Oretachin ni Tsubasa wa Nai
- Ori Sta
- Orient
- Orix Buffaloes
- Orthros no Inu
- Osake wa Fufu ni Nattekara
- Osama Game
- Osama Ranking
- Osananajimi ga zettai ni makenai love-come
- Osen
- Oshi ga Budokan Ittekuretara Shinu
- Oshigoto Danshi
- Oshiri Tantei
- Osomatsu-san
- Osozaki no Himawari
- Ossan's Love
- Otacool
- Otakara File
- Otaku Elf
- Otaku ni Koi wa Muzukashii
- Otenki One-san
- Otenki Sentai How Weather
- Otherside PIcnic
- Otoca Doll
- Otogi Jushi Akazukin
- Otoko no Kosodate
- Otoko wa Tsuraiyo
- Otokomeshi
- Otokotachi no Yamato
- Otome continue
- Otome wa Boku ni Koishiteru
- Otome Yokai Zakuro
- Otome-San
- Otona Anime
- Otona Joshi
- otona MUSE
- Otona no Boguya-san
- Otona no Kagaku Magazine
- Otona no Natsuyasumi
- Otona No Nurie
- Otona no Oshare Techo
- Otoyome Gatari
- Ougon no Gt
- Our Dearest Sakura (Doki no Sakura)
- OUR HOUSE
- Ouran Koko Host Club
- Ouroboros
- Outbreak Company
- Outlandar
- Over Drive
- Overlord
- Overman King-Gainer
- Overtake!
- Owarai Danshiko
- Oyasumi Punpun
- Oyuki Umi no Kina
- OZMAFIA!!
- Ozuma
- Please Tell Me! Galko-chan
- Seraph of the End
- Shomin Sample
- The Royal Tutor (Oshitsu Kyoshi Haine)
- Uncle from Another World