World file used by BZFlag, a 3D multi-player first person tank simulation game; contains a game world, or map, that defines 3D objects in plain text; supports land, water, meshes, and 3D shapes, such as boxes, cones, and spheres; may also be used to define game elements including teleporters and weapons.

BZW files are used to define custom new maps. They are loaded by the BZFlag server application on startup and distributed to client players when they join a game. They can be loaded using the "-world" command-line option on the BZFlag server. BZFlag, which stands for "Battle Zone capture the Flag," is an open source program that is supported for Mac, Windows, and Unix platforms. It uses OpenGL technology.