- Oniisama e...
- Onigiri ni Naritai Cogimyun
- Onihei: Sono Otoko, Heizou Hasegawa
- Oniichan wa Oshimai!
- Onikirimaru
- Onegai☆Twins
- Ookamikakushi
- Onigamiden
- Ongaku
- Ookami Kodomo no Ame to Yuki
- Ookami Shounen Ken
- Onmyouji
- Onimusha
- Ookami Shoujo to Kuro Ouji
- Ookami-san to Shichinin no Nakama-tachi
- Oniichan dakedo Ai sae Areba Kankeinai yo ne!
- Onihei
- Ore no Imouto ga Konnani Kawaii Wake ga Nai
- Oshiete Mahou no Pendulum: Rilu Rilu Fairilu
- Ore dake Level Up na Ken
- Osomatsu-kun (1988)
- Orient: Awajishima Gekitou-hen
- Oshare Kozou wa Hanamaru
- Ore Monogatari!!
- Oseam
- Orange
- Ore no Kanojo to Osananajimi ga Shuraba Sugiru
- Ore, Tsushima (ONA)
- Ore no Nounai Sentakushi ga, Gakuen Love Comedy wo Zenryoku de Jama Shiteiru
- Orenchi no Furo Jijou
- Osomatsu-san 2nd Season
- Ore dake Haireru Kakushi Dungeon
- Ore ga Suki nano wa Imouto dakedo Imouto ja Nai
- Osomatsu-san: Hipipo-Zoku to Kagayaku Kajitsu
- Ooya-san wa Shishunki!
- Osu!! Karate-bu
- Oooku
- Oshiete! Galko-chan
- Osomatsu-san Special
- Oshi ga Budoukan Ittekuretara Shinu
- Ore, Twintail ni Narimasu.
- Ore no Imouto ga Konnani Kawaii Wake ga Nai Specials
- Ooyukiumi no Kaina
- Osomatsu-san Movie: Gekijou Koukai Kinen - Original Tanpen Gekijou
- Osananajimi ga Zettai ni Makenai Love Comedy
- Orange: Mirai
- Ore wa Teppei
- Oretachi ni Tsubasa wa Nai: Hadairo Ritsu Kyuuwari Zou!?
- Osomatsu-kun
- Tezuka Osamu no Buddha: Akai Sabaku yo! Utsukushiku
