Magazine Series
- ALL OUT!!
- Always 3 chome no Yuhi
- Obey Me!
- Occultic;Nine
- OCTOPATH TRAVELER
- orange
- otona MUSE
- [Oshi no ko]
- Ookami kodomo no Ame to Yuki (Wolf Children)
- Okiku Furikabutte
- Okasan to Issho
- Okaeri Mone
- Okusama ga Seito Kaicho!
- Curious George
- Touch Detective Mushroom Garden
- Please Tell Me! Galko-chan
- Oshiri Tantei
- Osen
- Osomatsu-san
- Ochikobore Fruits Tarte
- Ochoyan
- Ossan's Love
- Otona no Natsuyasumi
- A Galaxy Next Door
- Otome Yokai Zakuro
- Onegai Teacher (Please Teacher!)
- Onegai My Melody
- Opanchu Usagi
- Omamori Himari
- Only Yesterday
- Onna Joshu Naotora
- Ojamajo
- Onichan Dakedo Ai Sae Areba Kankeinaiyone
- Onimai: I'm Now Your Sister!
- Otenki One-san
- Oneechan ga Kita
- A Girl & Her Guard Dog
- Oka-san Musume wo Yameteiidesuka?
- Omukaedesu.
- The Angel Next Door Spoils Me Rotten
- Ookami-san Series
- Okami Shojo to Kuro Oji
- Octave
- Gals Can't Be Kind to Otaku!? (Otaku ni Yasasshii Gal wa Inai!?)
- Otoca Doll
- Ori Sta
- Orient
- Orix Buffaloes
- Olympia Cuculus
- Olympic
- Alternative Girls
- Hortensia Saga
- Orenchi no Furo Jijyo
- Orange Page
- Onnamichi
- Online Game
- Only Mercedes
- Ooi! Tombo
- Overtake!
- Overlord
- All You Need Is Kill
- My Next Life as a Villainess: All Routes Lead to Doom!
- Trapped in a Dating Sim: The World of Otome Games is Tough for Mobs
- Kaiju Girl Caramelise
- Otokomeshi
- Ore, Twintail ni Narimasu.
- Shomin Sample
- Ore Ga Sukina No Ha Imotodakedo Imoto Janai
- Solo Leveling
- Where Have My Skirts Gone?
- Ore no Imoto ga Kon nani Kawaii wake ga nai
- Ore no Kanojo to Osananajimi ga Shuraba Sugiru
- Ore no Sora Series
- Ore o Suki nano wa Omae dake kayo
- Ore monogatari!!
- Otona no Oshare Techo
- Oh-oku ( Danjo Gyakuten)
- Ooya-san wa Shishunki !
- Ohoka Echizen
- Oyuki Umi no Kina
- Tenkuu Shinpan
- Okusama wa Toriatsukaichui
- Onna no Sono no Hoshi
- Osananajimi ga zettai ni makenai love-come
- You Can't Be in a Rom-Com with Your Childhood Friends!
- Omoi, Omoware, Furi, Furare
- Omoide no Marnie (When Marnie Was There)
- The Foolish Angel Dances with Demons
- Oshi ga Budokan Ittekuretara Shinu
- Ouran Koko Host Club
- Okami to Koshinryo (Wolf and Spice)
- The Royal Tutor (Oshitsu Kyoshi Haine)
- Osama Game
- Osama Ranking
- Otoko wa Tsuraiyo
- Seraph of the End
- Oda Nobuna no Yabou
- Oishinbo
- Odoru Daisosasen Series
- Ongaku to Hito