- Onii-chan Dakedo Ai Sae Areba Kankeinai yo ne! Specials
- Oniichan no Koto nanka Zenzen Suki ja Nai n da kara ne!!
- Oniichan wa Oshimai!
- Oniisama e...
- Onikirimaru
- Onipan!
- Only Yesterday
- Onmyou Hyakki Monogatari
- Onmyou Taisenki
- Onna Senshi Efe & Jira: Gude no Monshou
- Onsen Yousei Hakone-chan
- Ontama!
- Onyankopon
- Onyx Equinox
- Ookami Kakushi
- Ookami Kodomo no Ame to Yuki
- Ookami Kodomo no Ame to Yuki (Dub)
- Ookami Shoujo to Kuro Ouji
- Ookami Shoujo to Kuro Ouji OVA
- Ookami to Koushinryou (Shinsaku Anime)
- Ookami to Koushinryou II: Ookami to Kohakuiro no Yuuutsu
- Ookami-san to Shichinin no Nakama-tachi
- Ookami-san to Shichinin no Nakama-tachi (Dub)
- Ookamikakushi
- Ookiku Furikabutte
- Ookiku Furikabutte (Dub)
- Ookiku Furikabutte Season 2
- Ooya-san wa Shishunki!
- Ooyukiumi no Kaina
- Opus.COLORs
- Orange
- Orange (Dub)
- Orange: Mirai
- Orbital Era
- Ore dake Haireru Kakushi Dungeon
- Ore dake Haireru Kakushi Dungeon (Dub)
- Ore ga Ojousama Gakkou ni "Shomin Sample" Toshite Gets♥Sareta Ken
- Ore ga Suki nano wa Imouto dakedo Imouto ja Nai
- Ore Monogatari!!
- Ore Monogatari!! (Dub)
- Ore no Imouto ga Konnani Kawaii Wake ga Nai Specials
- Ore no Imouto ga Konnani Kawaii Wake ga Nai.: SD Chara ni Yoru Short Movie
- Ore no Nounai Sentakushi ga, Gakuen Love Comedy wo Zenryoku de Jama Shiteiru OVA
- Ore wa Teppei
- Ore wo Suki nano wa Omae dake ka yo
- Ore wo Suki nano wa Omae dake ka yo: Oretachi no Game Set
- Ore-sama Kingdom
- Ore-tachi ni Tsubasa wa Nai
- Ore, Tsushima
- Ore, Tsushima (ONA)
- Ore, Twintail ni Narimasu. (Dub)
- Ore, Twintails ni Narimasu.
- Oreca Battle
- Oreimo
- OreImo 2
- Orenchi no Furo Jijou
- OreShura
- Oretachi ni Tsubasa wa Nai: Hadairo Ritsu Kyuuwari Zou!?
- Oretachi ni Tsubasa wa Nai: Hadairo Ritsu Kyuuwari Zou!? (Dub)
- Oretachi ni Tsubasa wa Nai: Under the Innocent Sky. (Dub)
- Orient
- Orient (Dub)
- Orient: Awajishima Gekitou-hen
- Origin: Spirits of the Past
- Oruchuban Ebichu
- Osake wa Fuufu ni Natte kara
- Osamu Tezuka`s Buddha Movie 1
- Osananajimi ga Zettai ni Makenai Love Comedy
- Oseam
- Oshare Kozou wa Hanamaru
- Oshi ga Budoukan Ittekuretara Shinu
- Oshi ga Budoukan Ittekuretara Shinu (Dub)
- Oshiete Mahou no Pendulum: Rilu Rilu Fairilu
- Oshiete! Galko-chan
- Oshiete! Galko-chan OVA
- Oshiri Kajiri Mushi
- Osomatsu-kun
- Osomatsu-kun (1988)
- Osomatsu-san
- Osomatsu-san (Dub)
- Osomatsu-san 2
- Osomatsu-san 2nd Season (Dub)
- Osomatsu-san 3rd Season
- Osomatsu-san Movie
- Osomatsu-san Movie: Gekijou Koukai Kinen - Original Tanpen Gekijou
- Osomatsu-san Special
- Osomatsu-san Year-End Special
- Osomatsu-san: Hipipo-Zoku to Kagayaku Kajitsu
- Osomatsu-san: Ouma de Kobanashi
- Osu!! Karate-bu
- Otaku no Video
- OTMGirls no Yokiyoki Channel
- Otogi Juushi Akazukin
- Otogizoushi
- Otoko Ippiki Gaki Daishou
- Otome Game no Hametsu Flag shika Nai Akuyaku Reijou ni Tensei shiteshimatta...
- Otome Game no Hametsu Flag shika Nai Akuyaku Reijou ni Tensei shiteshimatta... (Dub)
- Otome Game no Hametsu Flag shika Nai Akuyaku Reijou ni Tensei shiteshimatta... OVA
- Otome Game no Hametsu Flag shika Nai Akuyaku Reijou ni Tensei shiteshimatta... OVA (Dub)
- Otome Game no Hametsu Flag shika Nai Akuyaku Reijou ni Tensei shiteshimatta... X
- Otome Game no Hametsu Flag shika Nai Akuyaku Reijou ni Tensei shiteshimatta... X (Dub)
- Otome Game Sekai wa Mob ni Kibishii Sekai desu
- Otome Game Sekai wa Mob ni Kibishii Sekai desu (Dub)
- Otome wa Boku ni Koishiteru
- Otome Youkai Zakuro
- Otona Joshi no Anime Time
- Otona no Bouguya-san
- Otona no Bouguya-san (Rimen)
- Otona no Bouguya-san 2nd Season
- Otonari ni Ginga
- Otonari no Tenshi-sama ni Itsunomanika Dame Ningen ni Sareteita Ken
- Ou Dorobou Jing in Seventh Heaven
- Ou Dorobou Jing in Seventh Heaven (Dub)
- Ougon Bat
- Ougon Senshi Gold Lightan
- Ouran High School Host Club
- Ouran Koukou Host Club (Dub)
- Ousama Game The Animation
- Ousama Game The Animation (Dub)
- Ousama Ranking
- Ousama Ranking (Dub)
- Oushitsu Kyoushi Haine
- Oushitsu Kyoushi Haine (Dub)
- Oushitsu Kyoushi Heine Movie
- Outbreak Company (Dub)
- Outbreak Company
- Outlanders
- Outlanders (Dub)
- Outlaw Star
- Oval x Over
- Over Drive
- Overlord
- Overlord (Dub)
- Overlord Combat Maid Chibi Comedy Spinoff
- Overlord II
- Overlord II (Dub)