| Otoshigoro Gakuen | 2022-01-27 | 6.80 (14) |
| Otoshima ~Shojo Kouryaku Hen~ | 2009-10-02 | 6.20 (9) |
| Otoshina | 2025-05-20 | - (1) |
| Otoshite Haramase! Misshitsu Kankin! Mahou Shoujo Arisarisa | 2012-07-06 | - (2) |
| Otoshite kara ga Honban Desu! -Kouryaku Taishou wa Delicate?- | 2014-09-08 | - |
| Otoshiya Kirin | 2022-08-31 | - |
| Ototama ~Boku-tachi Girls Band Desu~ | 2012-11-22 | 6.00 (51) |
| Otou-sama ni Naisho de Genkai made Hirogechaimashita ~ Koukakurou Sankai | 2009-07-10 | 5.60 (7) |
| Otou-san no Kodane de Haramasete! | 2016-08-14 | 6.80 (57) |
| Otou-san to Watashi | 2011-10-28 | 5.90 (13) |
| Otouto Freaks | 2011-10-07 | - (4) |
| Otouto Going My Way! | 2018-04-01 | - (1) |
| Otouto Nuigurumi | 2015-05-02 | - (4) |
| Otouto Scramble | 2016-04-21 | 5.60 (36) |
| Otouto Shibori ~Ane-tachi no Sei Kyouiku~ | 2013-02-01 | 6.10 (27) |
| Otouto o Aishite Yamanai Ane Arui wa Onii-chan ga Daisukikko na Imouto to no Taboo na Kankei | 2009-10-23 | 6.60 (22) |
| Otouto to, Natsumatsuri nite. | 2016-08-18 | - |
| Otouto wa Shota Bitch ~Takumi no Baai~ | 2012-04-01 | 4.70 (26) |
| Otouto: Nichijoukei | 2014-12-01 | - (3) |
| Otoutodeshi ga O**ho Yousei ni Natte Shimatta... | 2020-06-17 | - |
| Oto☆Puri ~Koiseyo! Otome Ouji-sama♪ Dokidoki Wedding Bell~ | 2008-12-19 | 6.80 (26) |
| Otpusti i zabud' | 2021-07-25 | - (1) |
| Otrjad zla | 2010-10-26 | - (2) |
| Otsuki-sama ni Kaeru Hi | 2002-12-19 | - |
| Otsuki-sama to Hiyoko | - | - |
| Otsumu Tenten ~Onii-chan to 3nin Musume no Mattari Ecchi na Nichijou~ | 2009-05-29 | 6.20 (6) |
| Otsutome Sakuya-san | 2023-06-02 | 7.00 (36) |
| Otter Tale | - | - (1) |
| Otter of My Life | - | - |
| Otto ni Ienai Gifu to no Kan'in ~Iya nanoni Wasurerarenaku Narisou~ | 2016-09-09 | 6.00 (32) |
| Otto no Inu Ma ni... ~Watashi Odosarete, Anata ni Ienai Koto Shimashita~ | 2017-10-27 | 7.40 (110) |
| Otto no Mae de Okasarete... | 2006-07-28 | 7.20 (81) |
| Otto no Shin'yuu no Chi*po o Kuwaeru Inran Bakunyuu Tsuma Fujii Yukari | 2007-12-30 | 5.80 (11) |
| Otto no Tomodachi ni Fellatio Shimashita... | 2021-01-23 | - |
| Otto no Tonari de Yobai Sareru Hounyuu Nikubenki Tsuma Yuuki Chigusa | 2008-08-29 | 6.60 (13) |
| Otto o Aisuru Bakunyuu Hitozuma-tachi ga Toshishita no Saru Seiyoku ni Jurin sarete Tsugou no ii Harami Omocha ni Ochiru Made | 2020-11-27 | 6.00 (143) |
| Otto yori Takumashii Mono de Tsukaretara… ~Musume ga Tsurete Kita Gaikoku Kareshi wa Haha no Watashi mo Onna ni Saseta~ | 2020-07-03 | 5.80 (72) |
| Ottoman Dreams: Rise of Süleiman | 2024-11-20 | - (1) |
| Ou no Mimi ni wa Todokanai! | 2016-12-22 | 7.20 (41) |
| Ou-sama Game | 1998-05-28 | - |
| Ou-sama game | 2010-02-16 | - |
| Ou-sama no Chou -Petit- | 2015-01-10 | - |
| Ou-sama no Hanaya | - | - |
| Ouchi de Kurasou! | 2008-08-29 | - |
| Ouchi ni Kaeru made ga Mashimaro Desu | 2017-07-28 | 7.40 (1042) |
| Oudou Yuusha | 1998-04-02 | 6.40 (11) |
| Ougon no Rashinban | 1990-10-05 | - (1) |
| Ouhime-sama ni Manabu! Shota Orc-kun no Tanezuke Kyouiku Nisshi | 2016-12-10 | - (1) |
| Ouji no Tanuki to Katsudon to | 2010-11-14 | - |
| Ouji to Dorei | 2014-12-28 | - |