- Otome Youkai Zakuro Picture Drama
- 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
- Ougon Bat
- Ougon Senshi Gold Lightan
- Ouran High School Host Club
- Ouran Koukou Host Club
- Ousama Game The Animation
- Ousama Ranking
- Ousama Ranking: Yuuki no Takarabako
- Oushitsu Kyoushi Haine
- Oushitsu Kyoushi Heine Movie
- Outbreak Company
- Outlanders
- Outlaw Star
- Outrageous! I Really Didn’t Want to Open a Training Class For Empresses!
- Oval x Over
- Over Drive
- Overlord
- Overlord Combat Maid Chibi Comedy Spinoff
- Overlord II
- Overlord III
- Overlord IV
- Overlord Movie 1: Fushisha no Ou
- Overlord Movie 2: Shikkoku no Eiyuu
- Overlord Movie 3: Sei Oukoku-hen
- Overlord Sei Oukoku-hen
- Overlord: Ple Ple Pleiades - Clementine Toubou-hen
- Overlord: Ple Ple Pleiades (OVA)
- Overlord: Ple Ple Pleiades 2
- Overlord: Ple Ple Pleiades 3
- Overlord: Ple Ple Pleiades 4
- Overman King Gainer
- Overmortal
- Overtake!
- Owari no Seraph
- Owari no Seraph 2nd Season
- Owari no Seraph: Kyuuketsuki Shahar
- Owari no Seraph: Nagoya Kessen-hen
- Owari no Seraph: Nagoya Kessen-hen - Owaranai Seraph - Nagoya Kessen-hen
- Owari no Seraph: Owaranai Seraph
- Owarimonogatari
- Owarimonogatari 2nd Season
- Oyayubi Hime Monogatari Movie
- Oz no Mahoutsukai (1986)
- Ozanari Dungeon: Kaze no Tou
- Ozmafia!!
- Ozuma
