BMD is a data container used by MMORPG computer game MU Online. Developer from WEBZEN, game’s producer, use BMD files to store 3D model, localization data, textual data, map designs, high-resolution textures, and animations for the game.

BMD are not to be edited, however, some unoffical tools that allow users to modify BMD files do exist. BMD files are stored in MU Online installation folder.