- Oath of the Gatewatch Costume
- Obaka-chan, Koigatariki Costume
- Obsolete Dream Costume
- Occult Academy Costume
- Occultic;Nine Costume
- Oda Nobuna no Yabou: Himesama to Issho Costume
- Odoru! Kremlin Kyuuden Costume
- Off Costume
- Ogenki Clinic Costume
- Oh My Goddess! Costume
- Oishinbo: Kyuukyoku tai Shikou, Chouju Ryouri Taiketsu!! Costume
- Ojisan to Marshmallow Costume
- Ojou-sama Yomeiri Kousou! Costume
- Ojousama no Gohoubi Costume
- Okami Kakushi Costume
- Okami-san Costume
- Okamisan and her Seven Companions Costume
- Okasubekarazu!! Junketsu Tokku! Costume
- Okobore Hime to Entaku no Kishi Costume
- Okusama ga Seitokaichō! Costume
- Okusama ga Seitokaichou! Costume
- Omamori Himari Costume
- Omamori no Kamisama Costume
- omega quintet Costume
- Omegarabirinsu Costume
- Omerta: Kochou no Yume no Hate Costume
- Omoi, Omoware, Furi, Furare Costume
- Omoide no Marnie Costume
- Onanie Master Kurosawa Costume
- Onanie Master Kurosawa: After the Juvenile Costume
- Once Upon a Time Costume
- One Missed Call Costume
- One Outs Costume
- One Piece Costume
- One Punch Man Costume
- One Room Costume
- One Week Friends Costume
- Onechanbara Costume
- Onee-chan wa Kushizashikou! ~Atashi no Kui de Tsuranuite Ageru~ Costume
- Oni Chichi: Rebuild Costume
- Onigiri Costume
- Oniichan dakedo Ai sae Areba Kankeinai yo ne! Costume
- Oniisama e... Costume
- Only Yesterday (1991 Film) Costume
- Onmyoji Costume
- Onmyou Taisenki Costume
- Onmyouji Costume
- Onsen Yousei Hakone-chan Costume
- Open Sesame Costume
- Orange Costume
- Orange Caramel Costume
- Orange Marmalade Costume
- Orange Yane no Chiisana Ie Costume
- Orc of Ambitia Costume
- Orc-sama to Majo ~Orcland Saga~ Costume
- Orcs Must Die! Unchained Costume
- Ore ga Heroine wo Tasukesugite Sekai ga Little Apocalypse! Costume
- Ore ga Ojousama Gakkou ni "Shomin Sample" Toshite Gets Sareta Ken Costume
- Ore Maou! ~Kudake Chitta Tamashii no Kakera o Shuushuu Seyo!~ Costume
- Ore no Kanojo ga Gachi Hentai Sugiru Costume
- Ore no Nounai Sentakushi ga, Gakuen Love Comedy wo Zenryoku de Jama Shiteiru Costume
- Ore to Akuma no Blues Costume
- Ore wa Teppei Costume
- Ore Yome! Costume
- Oreimo Costume
- Orenchi no Furo Jijō Costume
- Oreshura Costume
- Oretachi ni Tsubasa wa Nai Costume
- Origami Costume
- Osake wa Fuufu ni Natte kara Costume
- Osomatsu-kun Costume
- Osomatsu-san 2nd Season Costume
- Othello Costume
- Oto x Maho Costume
- Otome Costume
- Otome Riron to Sono Shuhen -Ecole de Paris- Costume
- Otome Switch Costume
- Otome wa Boku ni Koishiteru Costume
- Otome Yokai Zakuro Costume
- Otome ＊ Domain Costume
- Otona Joshi no Anime Time Costume
- Otona no Jikan Costume
- Otoshiya: The Degenerator Costume
- Ototsukai wa Shi to Odoru Costume
- Otouto no Otto Costume
- Otoyomegatari Costume
- Ouchi e Kaerou Costume
- Ougon Bat Costume
- Ouji ka Prince Costume
- Ouran High School Host Club Costume
- Ouritsu Ouji Gakuen Costume
- Ouroboros: Keisatsu wo Sabaku wa Ware ni Ari Costume
- Ousama no Koiasobi Costume
- Oushitsu Kyoushi Heine Costume
- Out Vegetables Costume
- Outbreak Company: Moeru Shinryakusha Costume
- Outlanders Costume
- Outlaw Star Costume
- Over the Garden Wall Costume
- Overlord Costume
- Overlord: Ple Ple Pleiades Costume
- Overwatch Costume
- Owari no Chronicle Costume
- Owari no Seraph: Ichinose Guren, 16-sai no Catastrophe Costume
- Oyasumi Punpun Costume
- Oz the Great and Powerful Costume
- Ozmafia Costume
- OZMAFIA!! Costume
