|This article is about a/an A.R. World in Kamen Rider Decade.|
The World of OOO (オーズの世界 Ōzu no Sekai) is the version of reality where Kamen Rider OOO takes place. The backdrop used to arrive in this world shows a diverse animal kingdom representing the Core Medals: including a lion, tiger, and a cheetah. Tsukasa Kadoya takes the role of Ankh in this world to the point of inheriting his distinctive red hairstyle and clothes.
- This lists only the characters featured in World of OOO, for the full cast list see Kamen Rider OOO.