Soundtrack Series Beginning with O
- Ochoyan
- Odoru Daisosasen Series
- Oh! My Girl!!
- Oh, My Dad!!
- Oh-oku ( Danjo Gyakuten)
- Oh-oku / Ooku
- Ohisama
- Ohitori sama
- Ohoka Echizen
- Oishi Propose
- Ojisan Ha Kawai I Mono Ga Osuki.
- Oka-san Musume wo Yameteiidesuka?
- Okaeri Mone
- Okami Shojo to Kuro Oji
- Okasan to Issho
- Okitegami Kyoko Series
- Okusama wa Toriatsukaichui
- Ol Nippon
- Omo ni Naiteimasu
- Omoide no Marnie (When Marnie Was There)
- Omoshiro Nankyoku Ryorinin
- Omotesandou Kouko Gassyobu!
- Omukaedesu.
- Once Upon a Time in High School
- Onihei Hankacho
- Oniyome Nikki
- Online Game
- Onna Joshu Naotora
- Onna Keiji Mizuki
- Onna wa sore wo yurusanai
- Ookami kodomo no Ame to Yuki (Wolf Children)
- Ore monogatari!!
- Ore no Hanashi wa Nagai
- Ore no Koto Sukidesho
- Orthros no Inu
- Osen
- Oshi ga Budokan Ittekuretara Shinu
- Osozaki no Himawari
- Ossan's Love
- Otaku ni Koi wa Muzukashii
- Otenki One-san
- Otoko wa Tsuraiyo
- Otokotachi no Yamato
- Otona Joshi
- Otona Koukou
- Otona no Natsuyasumi
- Ougon no Buta
- Our Dearest Sakura (Doki no Sakura)
- OUR HOUSE
- Ouroboros