- Oban Star Racers
- Ocha-ken
- Oden-kun
- Okusama wa Joshikousei
- One
- One Outs: Nobody Wins, but I!
- One Piece - New Year Present 2006
- One Piece - Soccer King
- One Piece Jidaigeki Special: Luffy Oyabun Torimonocho
- One Piece Movie: The Movie
- One Piece The Movie: Episode of Arabasta - The Desert Princess and the Pirates
- One Piece: Baron Omatsuri and the Secret Island
- One Piece: Baseball Special
- One Piece: Chopper Kingdom of Strange Animal Island
- One Piece: Clockwork Island Adventure
- One Piece: Dead End
- One Piece: Episode of Chopper Plus - Bloom in the Winter, Miracle Sakura
- One Piece: Jango's Dance Carnival
- One Piece: Karakuri Castle`s Mecha Giant Soldier
- One Piece: Open Upon The Great Sea! - A Father`s huge, HUGE Dream!
- One Piece: Protect! The Last Great Performance
- One Piece: Romance Dawn Story
- One Piece Special: Adventure in the Ocean's Navel
- Onegai my Melody
- Onegai my Melody - Kuru Kuru Shuffle!
- Onegai Teacher
- Onegai Twins
- Ontama!
- Ooedo Rocket
- Ookami to Kohaku-iro no Yuuutsu
- Ookami-kakushi
- Operation Sanctuary
- Oppai Life
- Origin: Spirits of the Past
- Osana Najimi to Doukyuusei
- Oshiete Re - Maid
- Otogi Jushi Akazukin
- Otogi Jushi Akazukin OAV
- Otogizoushi
- Otome wa Boku ni Koishiteru
- Our Jury Story
- Ouran High School Host Club
- OverDrive
- Overman King Gainer
