- Oval x Over
- Over Drive
- Overlord
- Overlord (Dub)
- Overlord Combat Maid Chibi Comedy Spinoff
- Overlord II
- Overlord II (Dub)
- Overlord III
- Overlord III (Dub)
- Overlord IV
- Overlord Movie 1: Fushisha no Ou
- Overlord Movie 2: Shikkoku no Eiyuu
- Overlord: Ple Ple Pleiades (OVA)
- Overlord: Ple Ple Pleiades - Clementine Toubou-hen
- Overlord: Ple Ple Pleiades 2
- Overlord: Ple Ple Pleiades 3
- Overlord: Ple Ple Pleiades 4
- Overman King Gainer
- Overman King Gainer (Dub)
- Overtake!
- Owari no Seraph
- Owari no Seraph (Dub)
- Owari no Seraph 2nd Season (Dub)
- 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
