Bowser's Sky Castle is the third and final level of World 6 of Paper Mario: Sticker Star. It is also the final level of the entire game.
With the final Royal Sticker in reach, Mario and Kersti head into Bowser's Castle to do battle with the Koopa tyrant himself. Before they can get anywhere, they are stopped by Kamek again who resorts to turning Mario's stickers into Sandles and making clones of himself. Mario quickly defeats him and treads ahead until he sees Princess Peach. Before he could reach her, Bowser steps in and the two old rivals get into the final fight. In the fight it is recommended to use all the powerful Thing stickers at your disposal and when the Thwomp comes down you need to make it fall, then use scissors on it to finish it off. After a very long fight, Mario defeats Bowser and claims the sixth and final Royal Sticker to his book. With that, Kersti finally returns them to the Sticker Comet and Mario, Peach, and even Bowser watch as the parade starts and the game ends. After that, the parade is accessible in Decalburg by a new pink Toad.
- Bowser's Sky Castle, along with Hither Thither Hill, are featured as settings on the Paper Mario stage in Super Smash Bros. for 3DS.