All Anime List "o" at Gogoanime
- Ore no Sora Keiji-hen
- ORESUKI Are you the only one who loves me?
- Ore wo Suki nano wa Omae dake ka yo: Oretachi no Game Set
- Oreca Battle
- Orenchi no Furo Jijou
- ORESUKI Are you the only one who loves me: Game Over
- Orient
- Orient Part 2
- 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 no Seiza
- Otaku no Video
- 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
- Ouran High School Host Club
- Outbreak Company
- Outlanders
- Oval x Over
- 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: The Sacred Kingdom
- Overlord: Ple Ple Pleiades
- Overlord: Ple Ple Pleiades - Clementine Toubou-hen
- Overlord: Ple Ple Pleiades 2
- Overlord: Ple Ple Pleiades 3