Paperback, Novel Series
- Always 3 chome no Yuhi
- Occultic;Nine
- OCTOPATH TRAVELER
- orange
- OZMAFIA!!
- [Oshi no ko]
- Oishii Coffee no Irekata
- Oishi Propose
- Okami Kakushi
- Ookami kodomo no Ame to Yuki (Wolf Children)
- Treat of Reincarnation
- Touch Detective Mushroom Garden
- Oshiri Tantei
- Osen
- Osomatsu-san
- Odekake Kozame
- Otogi Jushi Akazukin
- Otome Yokai Zakuro
- Onegai Twins
- Onegai Teacher (Please Teacher!)
- Onegai My Melody
- Ghostbook
- Omamori Himari
- Omiyasan
- Only Yesterday
- Ontama!
- Ojamajo
- Otome-San
- Onichan Dakedo Ai Sae Areba Kankeinaiyone
- Omukaedesu.
- Okane ga Nai!
- The Angel Next Door Spoils Me Rotten
- Ookami-san Series
- Okami Shojo to Kuro Oji
- The Diary of Ochibi-san
- Odd Taxi
- Orient
- Hortensia Saga
- Orthros no Inu
- Online Game
- Oh! My Girl!!
- Otome wa Boku ni Koishiteru
- My Next Life as a Villainess: All Routes Lead to Doom!
- Otokomeshi
- Ore, Twintail ni Narimasu.
- Shomin Sample
- Ore Ga Sukina No Ha Imotodakedo Imoto Janai
- Ore no Imoto ga Kon nani Kawaii wake ga nai
- Ore no Kanojo to Osananajimi ga Shuraba Sugiru
- Ore no Sora Series
- Ore no nonai sentakushi ga gakuen Love comedy wo Zenryoku de Jyama Shiteiru
- Ore o Suki nano wa Omae dake kayo
- Ore monogatari!!
- Ohoka Echizen
- Husband's lover
- Onna wa sore wo yurusanai
- Osananajimi ga zettai ni makenai love-come
- Omoi, Omoware, Furi, Furare
- Omoide no Marnie (When Marnie Was There)
- Okitegami Kyoko Series
- Okami to Koshinryo (Wolf and Spice)
- Osama Game
- Osama Ranking
- Royal Space Force - The Wings of Honneamise
- Otokotachi no Yamato
- Otoko wa Tsuraiyo
- Seraph of the End
- Oda Nobuna no Yabou
- Oishinbo
- Odoru Daisosasen Series
- Omoshiro Nankyoku Ryorinin
- Ongaku to Hito
- Ongaku-shi ga Kakanai Jpop Hihyo
- Oniyome Nikki
- Onihei Hankacho
- Onigiri
- Onimusha
- Onigamiden