Doien is the homeworld of the Pilots on Farscape, located at the edge of Grey Space. It is first seen via flashback in the episode "The Way We Weren't" and reappears as the main setting in the Red Sky At Morning arc of the Farscape comic book.

The planet is a swampy, forested world, featuring marshes, mountains, and lagoons that can accommodate Leviathan landings. It orbits a ringed sun.

During the early stages of the Kkore invasion of the galaxy, the Grennij invaded Doien, slaughtering dozens of native Pilots to set up an enormous command center.

The planet is ultimately liberated by a group of deserted Peacekeepers and the Moya crew.