Kamen Rider OOO (仮面ライダーオーズ/ Kamen Raidā Ozu ? ) adalah seri kedua belas dalam periode Heisei menjalankan dari Kamen Rider Series , dan yang pertama kali dua puluh keseluruhan. Ia mulai ditayangkan pada tanggal 5 September 2010, minggu berikut kesimpulan dari Kamen Rider W ,  bergabung Tensou Sentai Goseiger dalam Super Hero Time lineup. seri 'tituler ini Kamen Rider membuat penampilan cameo dalam film Kamen Rider W Selamanya: A sampai Z / The Memories Gaia Takdir . The slogannya untuk seri adalah "Aku akan mengubah!" (俺が変身 Ore ga suru Henshin! ? ).
OOO is written by Yasuko Kobayashi, known for the screenplays of Seijuu Sentai Gingaman, Mirai Sentai Timeranger Kamen Rider Ryuki, Den-O, and Samurai Sentai Shinkenger. The creature designers are Yutaka Izubuchi, known for his work on the Lords in Kamen Rider Agito, and Tamotsu Shinohara, known for his work on the Mirror Monsters of Ryuki and the Orphnoch of Kamen Rider 555. Unlike several previous Heisei Rider Series, no alternate name has been given yet for the three O's in the title (Ｗ（ダブル） read as "Double" and 555（ファイズ） read as "Φ's/Phi's/Faiz") aside from an alternate spelling of the name of the main Kamen Rider: Ooz. Both "OOO" and "Ooz" are intended to be read as "O's", referring to the multiple uses of the letter O in the title as well as "multiple kings" (王ｓ Ōzu?). The title OOO signifies the three medals that the main Kamen Rider uses to transform as well as being representative of the infinity symbol () with an additional circle.
Main article: List of Kamen Rider OOO characters
Eiji Hino is a man who has no dreams, no job, and no family. When animal-like monsters called Greeed awaken after their 800 year slumber to attack humans and feed off of their desire, a bird-type Greed called Ankh gives Eiji a belt and three Medals to fight the Greed. This allows Eiji to become Kamen Rider OOO. The mysterious Kougami Foundation approaches him and begins assisting him in his fight against the Greed, but their true motives are not clear. When Eiji fights for the first time, he starts to realize what it means "to be alive".
Main article: List of Kamen Rider OOO episodes
Each episode title of Kamen Rider OOO consists of three objects featured in the episode.
Medals, Underwear, and a Mysterious Arm (メダルとパンツと謎の腕 Medaru to Pantsu to Nazo no Ude?)
Desire, Ice Pops, and Presents (欲望とアイスとプレゼント Yokubō to Aisu to Purezento?)
A Cat, Evolution, and a Glutton (ネコと進化と食いしん坊 Neko to Shinka to Kuishinbō?)
Doubt, a Picture Message, and a Helping Hand (疑いと写メと救いの手 Utagai to Shame to Sukui no Te?)
A Game of Tag, a Nest, and a Rich Girl (追いかけっこと巣とセレブ Oikakekko to Su to Serebu?)
Fashion, a Contract, and the Strongest Combo (お洋服と契約と最強コンボ Oyōfuku to Keiyaku to Saikyō Konbo?)
A Lousy Husband, a Trap, and a Jackpot (ダメ亭主と罠と大当たり Dame Teishu to Wana to Ōatari?)
Sabotage, Having No Greed, and Taking a Break (サボりと無欲と休憩中 Sabori to Muyoku to Kyūkeichū?)
Drenched, the Past, and the Scorching Combo (ずぶぬれと過去と灼熱コンボ Zubunure to Kako to Shakunetsu Konbo?)
A Fist, an Experiment, and a Super Bike (拳と実験と超バイク Kobushi to Jikken to Chō Baiku?)
A Traveller, a Swallowtail, and a Celebrity (旅人とアゲハ蝶と有名人 Tabibito to Agehachō to Yūmeijin?)
An Eel, the World, and the Gravity Combo (ウナギと世界と重力コンボ Unagi to Sekai to Jūryoku Konbo?)
A Siamese Cat, Stress and the Genius Surgeon (シャム猫とストレスと天才外科医 Shamu Neko to Sutoresu to Tensai Gekai?)
Pride, Surgery, and a Secret (プライドと手術と秘密 Puraido to Shujutsu to Himitsu?)
The Medal Struggle, the Transport Truck, and the Container (メダル争奪と輸送車と器 Medaru Sōdatsu to Yusōsha to Utsuwa?)
An End, the Greeed, and a New Rider (終末とグリードと新ライダー Shūmatsu to Gurīdo to Shin Raidā?)
The Kendo Girl, Oden, and the Splitting Yummy (剣道少女とおでんと分離ヤミー Kendō Shōjo to Oden to Bunri Yamī?)
Destruction, Motives, and the Eel Whip (破壊と理由とウナギムチ Hakai to Riyū to Unagi Muchi?)
The Red Medal, the Detective, and Betrayal (赤いメダルと刑事と裏切り Akai Medaru to Keiji to Uragiri?)
The Decoy, the Qualifications, and the Blazing Combo (囮（おとり）と資格と炎のコンボ Otori to Shikaku to Honō no Konbo?)