Upload a Custom Map to Your GMod Server

A custom Garry's Mod map is a .bsp file. Put it in the server's maps folder, tell the server to start on it, and make sure your players can download it when they join. If the map is already on the Steam Workshop, the quicker route is to add it to your collection instead: Add a Steam Workshop collection to your GMod server covers that.

Upload the map file

1. Get the map's .bsp file. Maps from other sites often arrive in a .zip.
2. Open your server in the dashboard and go to the File Manager tab.
3. Open garrysmod, then maps. The Garry's Mod wiki puts server maps in garrysmod/maps/.
4. Press Upload and pick the file, or drag it onto the list. If you have a .zip, upload it and use Extract here on it, then delete the .zip.

A browser upload stops at 100 MB a file. For a bigger map, use SFTP: the File Manager points you to it, and the connection details are in the Settings tab.

Some maps come with extra files beside the .bsp, such as a .nav file. The wiki lists bsp, nav, txt and lmp as the file types in an addon's maps folder. Upload them to the same folder as the .bsp.

Start the server on the map

1. Open the Startup tab.
2. In the Game card, type the map's name in the Map box. Use the file name without the .bsp ending. A file called gm_mymap_v2.bsp is entered as gm_mymap_v2.
3. Press Save changes. If the server is running, press Restart now in the Restart to apply message. If it is offline, press Start.

The Map box takes letters, numbers, dashes and underscores. The map name has to match the file exactly, or the server can't find it.

To move a running server to the new map without a restart, send changelevel gm_mymap_v2 from the Console tab. The wiki describes this as the way to "gracefully change the active map". The Map box still decides which map the server starts on after a restart.

Let players download the map

Players need the map on their own computer. The wiki says that fetching content on the fly "will never work for a map", so the map has to be served to them before they join. It lists three ways to serve content:

1. Workshop. Upload the map to the Steam Workshop and add it to your collection. If the server is running a map that is also in the collection (matched by its .bsp name), the wiki says it "will be automatically marked for download by clients". The wiki ranks it the fastest of the three for players.
2. FastDL. Players download from a web server you run yourself, using sv_downloadurl, and each file is marked with resource.AddFile. The wiki says you need a separate web server for it.
3. The server itself. Set sv_allowdownload 1 and mark the file with resource.AddFile. The wiki calls this obsolete because it is limited to 64 kb/s, and warns that it opens the server to exploits.

To mark a map file for download, create a Lua file in garrysmod/lua/autorun/server/ with this line, using your map's name:

resource.AddFile( "maps/gm_mymap_v2.bsp" )

The path is relative to garrysmod/, and the file has to exist on the server. Don't add .bz2 to the path.

Common problems

1. The server starts on the old map. The Map box wasn't saved, or the server wasn't restarted after saving. Check the Startup tab.
2. The map isn't found. The name in the Map box doesn't match the .bsp file. Check the spelling and that you left off the .bsp ending.
3. Players can't join or get stuck downloading. They don't have the map. Use one of the three methods above. The wiki notes a limit of 8192 downloadable files in total, shared by every resource.Add call.

Checked against the Facepunch Garry's Mod wiki and our panel, October 2026.