Drama CD Series Beginning with O
- My Next Life as a Villainess: All Routes Lead to Doom!
- Oda Nobuna no Yabou
- Oda Shinamon Nobunaga
- Ojisama (warai) Series
- Ojisama Senka
- Okami to Koshinryo (Wolf and Spice)
- One Punch Man
- Oneechan ga Kita
- Onichan Dakedo Ai Sae Areba Kankeinaiyone
- Onkyokaiwa
- Online Game
- Onosaka, Konishi no O+K(OTASUKE)
- Opus.COLORs
- Ore no Kanojo to Osananajimi ga Shuraba Sugiru
- Ore, Twintail ni Narimasu.
- Osomatsu-san
- Otenki Sentai How Weather
- Otome wa Boku ni Koishiteru
- Overlord
- Please Tell Me! Galko-chan
- Seraph of the End
- Shomin Sample
- The Royal Tutor (Oshitsu Kyoshi Haine)