Banjo-Threeie is a rumored third entry for the Banjo-Kazooie series that was supposedly intended to be made for the Nintendo GameCube in the early 2000s.

The game was first hinted at the end of Banjo-Tooie, in which the character Gruntilda jokingly says "Just you wait until Banjo-Threeie...", which was speculated to be evidence that the game was at one point planned by fans.

At SpaceWorld 2000, a small animation featuring characters from the Banjo-Kazooie series was shown, showing off the presence of Rare during the GameCube era of gaming. The animation features Banjo, Kazooie and Mumbo Jumbo being chased by enemies from Banjo-Tooie, all using their models from the game.

In 2002, Rare was brought by Microsoft, which caused various games developed for Nintendo systems at the time to move platforms, which would've included Banjo-Threeie.

Decades later, in 2020, the developer Gregg Mayles confirmed it to be simply a joke that fans took at face value, and the SpaceWorld demo was confirmed to simply be a showcase of how many N64 models the GameCube could render at once.

According to Mayles, a game in the same style as the first two wasn't in the plans, and they went through three different concepts, until setting on what became Banjo-Kazooie: Nuts & Bolts.