Your favorite games don't need to end just because you've finished them. Fans, hobbyists, and aspiring game developers from around the world can add to or modify their favorite games by creating "mods". Whether it's adding new graphical features, crafting new items, or creating new stories, mods can breathe new life into games of all types. Steam makes it easy to find and try these mods for any game in your library that supports modding.
Many mods are free and range in scope from smaller changes here or there to entirely new items, characters, maps, or missions. Other mods may add expansive community-created content equaling hours of new gameplay and storyline, or even an entirely new game built from the ground up.
Supporting mods means supporting their authors, and encouraging them to update their existing mods and make more and better mods in the future. Some mods can even grow into full stand-alone commercial products. Counter-Strike, Dota 2, and Team Fortress all began their life as mods.
You may just stumble across the next big thing and help it grow.
Does my favorite game have mods?
Many games support mods through the Steam Workshop, where you can easily browse for new content and have it automatically appear in your game. You can also find mods related to a game by checking for the "Community-made Mods" section on its store page. If a game doesn't support mods, you can tell the developers you'd like to see that feature by starting up a discussion on the game's Community Hub.
Do I need to own the game that the mod is made for?
Yes. Mods alter or add to the game they're created for, so you must have that game in your Steam library to utilize them.
Why are some mods free and other cost money?
Each mod author decides whether they think there is enough customer interest in their mod to list it for sale. Just like buying a game, paying for a mod helps to support and reward the team (sometimes consisting of just one person) who have worked hard to create that new content.
Are mods officially endorsed by Steam or the game's developers?
Unless specifically stated otherwise, mods are created by fans in a game's community for their fellow players. Developers are not typically involved with mods or their creation, other than allowing their games to support them. If you're not clear about a mod in any way, check the Community Hub for more information and help. Mods can have comments, reviews, and ratings like other content on Steam.
I've made a mod for a game. How can I get it on Steam?
If your content is intended for a game's Workshop, follow the directions from the game's developers to learn how to upload that content, as each game may have a slightly method for doing so. If you have a Source Engine mod and would like to distribute or sell your mod through the Steam store, please submit your mod to Greenlight where the community can vote for the next games and mods they wish to see made available via Steam. This is a great way to build awareness and gather feedback on your work.
For more information on mods that utilize the Source Engine (games such as Half-Life 2, Team Fortress 2, Left 4 Dead, and Portal) please see our Source mods documentation.