- One Piece: The Movie 13 - Film: Gold
- One Piece: The Movie 14 - Stampede
- One Piece: The Movie 8 - Adventures in Alabasta
- One Piece: Unwavering Justice! The Navy's Proud Log!
- One Pound Gospel
- One Punch Man
- One Punch Man 2nd Season
- One Punch Man 2nd Season Commemorative Special
- One Punch Man 2nd Season Specials
- One Punch Man 3: Specials
- One Punch Man Specials
- One Punch Man: Road to Hero
- One Room
- One Room Second Season
- One Room Second Season Special
- One Room Third Season
- One Step Toward Freedom
- One Way or Another
- One Week Friends
- One-Million Year Trip: Bander Book
- One-Punch Man Season 3
- One: Kagayaku Kisetsu e
- Oneechan ga Kita
- Oneechan ga Kita: Hajimete no… Kitaa!
- Onegai My Melody
- Onegai My Melody Sukkiri♪
- Onegai My Melody: Kuru Kuru Shuffle!
- OniAi
- OniAi Specials
- Onigiri
- Onimai: I'm Now Your Sister!
- Onimai: I'm Now Your Sister! (Uncensored)
- Onimomomomo
- Onimusha
- Onipan!
- Only Yesterday
- Onmyo Kaiten Re:Birth Verse
- Onmyouji
- Onyankopon
- Ōoku: The Inner Chambers
- Oomuro-ke: Dear Friends
- Oomuro-ke: Dear Sisters
- Ooya-san wa Shishunki!
- Open Your Mind
- Operation Han-Gyaku-Sei Million Arthur
- Operation Han-Gyaku-Sei Million Arthur 2nd Season
- Opus.COLORs
- Orange
- Orange: Mirai
- Ore ga Ojousama Gakkou ni "Shomin Sample" Toshite Gets♥Sareta Ken Specials
- Ore ga Suki nano wa Imouto dakedo Imouto ja Nai Specials
- Ore no Nounai Sentakushi ga, Gakuen Love Comedy wo Zenryoku de Jama Shiteiru OVA
- Ore no Sora Keiji-hen
- Ore wo Suki nano wa Omae dake ka yo: Oretachi no Game Set
- Oreca Battle
- Orenchi no Furo Jijou
- Oreshura
- ORESUKI Are you the only one who loves me: Game Over
- ORESUKI Are you the only one who loves me?
- Orient
- Orient Part 2
- Origin: Spirits of the Past
- Original Dirty Pair: Flight 005 Conspiracy
- Orochi, the Eight-Headed Dragon
- Osake wa Fuufu ni Natte kara: Yuzu Atsukan
- Osamake: Romcom Where The Childhood Friend Won't Lose!
- Oshiete Mahou no Pendulum: Rilu Rilu Fairilu
- Osomatsu-kun (1988)
- Osomatsu-san 3rd Season
- Otaku Elf
- Otaku no Seiza
- Otaku no Video
- Otherside Picnic
- Otherworldly Evil Monarch
- Otogi Zoshi: The Legend of Magatama
- Otome Game no Hametsu Flag shika Nai Akuyaku Reijou ni Tensei shiteshimatta... OVA
- Otome Youkai Zakuro Picture Drama
- Otona no Bouguya-san 2nd Season
- Our Dating Story: The Experienced You and The Inexperienced Me, Kimizero
- Our Home's Fox Deity
- Our Last Crusade or the Rise of a New World
- Our Last Crusade or the Rise of a New World Season 2
- Our love has always been 10 centimeters apart.
- Ouran High School Host Club
- Outbreak Company
- Outburst Dreamer Boys
- Outlanders
- Outlaw Star
- Oval x Over
- Over Drive
- Over Goddess
- Over the Divine Realms
- Over the Sky
- Overflow (TV ver.)
- Overflow (Uncensored)
- Overlord
- Overlord II
- Overlord III
- Overlord IV
- Overlord Movie 1: The Undead King
- Overlord Movie 2: The Dark Hero
- Overlord: Ple Ple Pleiades
- Overlord: Ple Ple Pleiades - Clementine Toubou-hen
- Overlord: Ple Ple Pleiades 2
- Overlord: Ple Ple Pleiades 3
- Overlord: Ple Ple Pleiades 4
- Overlord: The Sacred Kingdom
- Overman King Gainer
- Overtake!
- Owari no Seraph: Vampire Shahar
- Owarimonogatari
- Owarimonogatari Second Season
- Ozanari Dungeon: Kaze no Tou
- Ozma
- Ozmafia!!
- Pachislo Kizoku Gin
- Painting Jianghu: The Legend of Tiangang
- Painting Rivers and Lakes 4
- Painting Rivers and Lakes 5
- Painting Rivers and Lakes 6
- Pale Cocoon
- Pan de Peace!
- Panda no Daibouken
- Pandora Hearts Omake
- Pandora in the Crimson Shell
- Pandora to Akubi
- PandoraHearts
- Pani Poni Dash!
- Paniponi Dash!: Danjite Okonaeba Kishin mo Kore wo Saku
- Pankunchi
- Pants no Ana: Mambo de Ganbo!
- Panty & Stocking in Sanitarybox
- Panty & Stocking with Garterbelt
- Panty & Stocking with Garterbelt 2nd Season
- Panyo Panyo Di Gi Charat
- Panzer Dragoon
