WD is a file extension specific to series of games such as Earth 2140, Earth 2150, Earth 2150: Lost Souls, Earth 2150: The Moon Project and Earth 2160. These are real-time strategies developed and published by Jelsoft Enterprises Ltd.

WD are files used to store many of the game's resources. These include graphics, textures, 3D models and sound materials. These files are also supported by the map editor for Earth 2150 World Creator and Earth 2160 World Creator. The WD Pack utility also supports these files. WD Pack is a module developed by Mariusz Czyz and is part of EarthC Studio for Earth 2160.