Upload Custom Addons to Your GMod Server

Most Garry's Mod addons come from the Steam Workshop, and the Workshop tab handles those. An addon you downloaded from a forum, GitHub or a developer's own site comes as a folder instead. This guide puts that kind of addon on your server by hand, in garrysmod/addons.

For Workshop addons, use Add a Steam Workshop collection to your GMod server. Scripts you bought on GmodStore install from the GmodStore tab instead.

Check the addon's folder first

An addon is a folder, and the Garry's Mod wiki asks for two things from it:

• A tidy name. Use lowercase letters, numbers, underscores and dashes, such as cool_space_laser. A name like My Cool Addon! has capitals, spaces and a special character, and the wiki lists those as issues.
• The game's own layout inside. An addon's folder copies the layout of the garrysmod folder, with folders such as lua, models, materials, maps and sound sitting directly in it. The wiki adds that an addon only needs the folders it has files for.

Open the download and look inside. If the folder you want has another folder of the same name inside it, with lua and the rest one level further down, use the inner one. Otherwise the server won't find the files.

Upload it

1. Zip the addon's folder on your computer, so the .zip holds the one addon folder.
2. Open your server in the dashboard and go to the File Manager tab.
3. Open garrysmod, then addons.
4. Press Upload and pick the .zip, or drag it onto the list. Browser uploads stop at 100 MB a file, so for something bigger use SFTP and drop the folder straight into garrysmod/addons.
5. Click the .zip and use Extract here. Check that the addon's folder is now inside addons, then delete the .zip.

Manage your server files covers the File Manager in more detail.

Restart so it loads

Press Restart on the Console tab. The wiki says addons are loaded "during the process of loading a map or connecting to a server", so a restart is the surest way to have the server pick the new folder up. Watch the Console while it starts for error lines that mention the addon's name.

To remove the addon later, stop the server, delete its folder from garrysmod/addons in the File Manager, and start it again.

Players and the addon's files

Whether players need to download anything depends on what is inside the addon:

• Lua files. The wiki says .lua files "are NOT considered content, they are downloaded through separate processes and require no additional setup". An addon that is only code needs nothing more.
• Models, materials, sounds and maps. Players need those files on their own computer, or they see errors and missing textures. The wiki lists three ways to serve them: the Steam Workshop with resource.AddWorkshop, FastDL from a web server of your own, or the server itself with sv_allowdownload 1.

To send a file from the server, add a line like this to a Lua file in garrysmod/lua/autorun/server/:

resource.AddFile( "models/my/model.mdl" )

The wiki says this call also adds the related files a model needs, such as its .vvd and .phy files. The path is relative to garrysmod/. Don't put addons/<addonname>/ in it, because that folder is mounted as if it sat in the root of garrysmod/.

Add a Steam Workshop collection to your GMod server explains resource.AddWorkshop and the panel's workshop.lua file.

Common problems

1. Nothing changed after the restart. The addon is probably one folder too deep, or its name has capitals or spaces. Move the right folder directly under addons and rename it.
2. Players see errors or missing textures. They are missing the addon's models or materials. Serve those files using one of the methods above.
3. The server won't start after adding it. Stop the server, delete the new folder from garrysmod/addons, and start again. Then read the console for the addon's error.

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