O
- Occultic Nine
- Ochibi-san
- Ochikobore Fruit Tart
- Oda Cinnamon Nobunaga
- Oda Nobuna no Yabou
- Odd Taxi
- Odd Taxi Movie: In the Woods
- Oemojisangjuui
- Ojamajo Doremi
- Ojamajo Doremi Dokkaan!
- Ojamajo Doremi Sharp
- Ojisan to Marshmallow
- Ojou to Banken-kun
- Okashi na Tensei
- Okusama ga Seitokaichou!
- Okusama ga Seitokaichou! Season 2
- Omae wa Mada Gunma wo Shiranai
- Omamori Himari
- Omoide no Marnie
- Omoi Omoware Furi Furare
- Onegai Teacher
- Onegai Twins
- One Off
- One Outs
- One Piece
- One Piece 3D2Y: Ace no shi wo Koete! Luffy Nakama Tono Chikai
- One Piece 3D: Mugiwara Chase
- One Piece: Adventure of Nebulandia
- One Piece: Episode of East Blue
- One Piece: Episode of Luffy - Hand Island no Bouken
- One Piece: Episode of Merry - Mou Hitori no Nakama no Monogatari
- One Piece: Episode of Nami - Koukaishi no Namida to Nakama no Kizuna
- One Piece: Episode of Sabo - 3 Kyoudai no Kizuna Kiseki no Saikai to Uketsugareru Ishi
- One Piece: Episode of Sorajima
- One Piece: Heart of Gold
- One Piece: Mamore! Saigo no Dai Butai
- One Piece: Nenmatsu Tokubetsu Kikaku! Mugiwara no Luffy Oyabun Torimonochou
- One Piece: Oounabara ni Hirake! Dekkai Dekkai Chichi no Yume!
- One Piece: Romance Dawn Story
- One Piece: Taose! Kaizoku Ganzack
- One Piece: Umi no Heso no Daibouken-hen
- One Piece Fan Letter
- One Piece Film: Gold
- One Piece Film: Red
- One Piece Film: Strong World
- One Piece Film: Strong World Episode 0
- One Piece Film: Z
- One Piece Live Action
- One Piece Movie 1: The Great Gold Pirate
- One Piece Movie 2: Nejimaki-jima no Daibouken
- One Piece Movie 3: Chinjuu-jima no Chopper Oukoku
- One Piece Movie 4: Dead End no Bouken
- One Piece Movie 5: Norowareta Seiken
- One Piece Movie 6: Omatsuri Danshaku to Himitsu no Shima
- One Piece Movie 7: Karakuri-jou no Mecha Kyohei
- One Piece Movie 8: Episode of Alabasta - Sabaku no Oujo to Kaizoku-tachi
- One Piece Movie 9: Episode of Chopper Plus - Fuyu ni Saku Kiseki no Sakura
- One Piece Movie 14: Stampede
- One Punch Man
- One Punch Man Season 2
- One Punch Man Season 2 Specials
- One Punch Man Specials
- One Room
- One Room Hiatari Futsuu Tenshi-tsuki
- One Room Second Season
- One Room Third Season
- Ongaku Shoujo
- Oni: Kamigami Yama no Onari
- Onigiri
- Onihei
- Oniichan dakedo Ai sae Areba Kankeinai yo ne!
- Oniichan no Koto nanka Zenzen Suki ja Nai n da kara ne!!
- Oniichan wa Oshimai!
- Onimusha
- Ooi! Tonbo
- Ookamikakushi
- Ookami Kodomo no Ame to Yuki
- Ookami Shoujo to Kuro Ouji
- Ookami to Koushinryou
- Ookami to Koushinryou: Merchant Meets the Wise Wolf
- Ookami to Koushinryou II
- Ookiku Furikabutte
- Ookiku Furikabutte: Natsu no Taikai-hen
- Oomuro-ke: Dear Friends
- Oomuro-ke: Dear Sisters
- Oooku
- Ooyasan wa Shishunki!
- Ooyukiumi no Kaina
- Orange
- Orange: Mirai
- Oreca Battle
- Ore dake Haireru Kakushi Dungeon
- Ore dake Level Up na Ken
- Ore ga Ojousama Gakkou ni "Shomin Sample" Toshite Gets Sareta Ken
- Ore ga Suki nano wa Imouto dakedo Imouto ja Nai
- Ore Monogatari!!
- Ore no Imouto ga Konnani Kawaii Wake ga Nai
- Ore no Imouto ga Konnani Kawaii Wake ga Nai 2
- Ore no Kanojo to Osananajimi ga Shuraba Sugiru
- Ore no Nounai Sentakushi ga, Gakuen Love Comedy wo Zenryoku de Jama Shiteiru
- Oretachi ni Tsubasa wa Nai: Under the Innocent Sky
- Ore Twintail ni Narimasu
- Ore wa Subete wo "Parry" suru: Gyaku Kanchigai no Sekai Saikyou wa Boukensha ni Naritai
- Ore wo Suki nano wa Omae dake ka yo
- Ore wo Suki nano wa Omae dake ka yo: Oretachi no Game Set
- Orient
- Orient: Awajishima Gekitou-hen
- Oroka na Tenshi wa Akuma to Odoru
- Osake wa Fuufu ni Natte kara
- Osananajimi ga Zettai ni Makenai Love Comedy
- Oshiete! Galko-chan
- Oshi ga Budoukan Ittekuretara Shinu
- Oshi no Ko
- Oshi no Ko Season 2
- Osomatsu-san
- Osomatsu-san Season 2
- Osomatsu-san Season 3
- Otaku no Video
- Otogi Story Tenshi no Shippo
- Otome Game no Hametsu Flag shika Nai Akuyaku Reijou ni Tensei shiteshimatta
- Otome Game no Hametsu Flag shika Nai Akuyaku Reijou ni Tensei shiteshimatta X
- Otome Game Sekai wa Mob ni Kibishii Sekai desu
- Otona no Bouguya-san
- Otona no Bouguya-san (Rimen)
- Otona no Bouguya-san II
- Otonari ni Ginga
- Otonari no Tenshi-sama ni Itsunomanika Dame Ningen ni Sareteita Ken
- Ou Dorobou Jing
- Ougon Yuusha Goldran
- Ouran Koukou Host Club
- Ouritsu Uchuugun: Honneamise no Tsubasa
- Ousama Game The Animation
- Ousama Ranking
- Ousama Ranking: Yuuki no Takarabako
- Oushitsu Kyoushi Heine
- Oushitsu Kyoushi Heine Movie
- Outbreak Company
- Overlord
- Overlord: Ple Ple Pleiades
- Overlord: Ple Ple Pleiades 2
- Overlord: Ple Ple Pleiades 3
- Overlord II
- Overlord III
- Overlord IV
- Overlord Movie 1: Fushisha no Ou
- Overlord Movie 2: Shikkoku no Eiyuu
- Overtake!
- Owarimonogatari
- Owarimonogatari Season 2
- Owari no Seraph
- Owari no Seraph: Nagoya Kessen-hen
- Ozma