All Anime List "o" at Gogoanime
- Offside (TV)
- Oh! Edo Rocket
- Ohayou! Spank (Movie)
- Oishinbo
- Oishinbo: The Japan-America Rice War
- Ojamajo Doremi Sharp Movie
- Ojamajo Doremi: Owarai Gekijou
- Ojamanga Yamada-kun (Movie)
- Ojisan and Marshmallow
- Ojisan and Marshmallow Episode 13: Hige-san and Marshmallow
- Okaimono Panda!
- Okama Report
- Okashi na Sabaku no Suna to Manu
- Okitsura: Fell in Love with an Okinawan Girl, but I Just Wish I Know What She's Saying
- Okoshiyasu, Chitose-chan
- Okoshiyasu, Chitose-chan Recaps
- Okubyou na Venus
- OL Kaizou Kouza
- Omamori Himari
- Omoi no Kakera
- Only Yesterday
- On Your Mark
- Onara Goro
- One Off
- One Outs
- One Piece
- One Piece - Wano Kuni SP
- One Piece 3D2Y: 15th Anniversary
- One Piece 3D: Gekisou! Trap Coaster
- One Piece 3D: Strawhat Chase
- One Piece Fan Letter
- One Piece: The Movie 13 - Film: Gold
- ONE PIECE FILM GOLD 〜episode 0〜
- One Piece Film: Red
- One Piece: The Movie 10 - Strong World
- One Piece Film: Strong World Episode 0