Recommended Copyleft Licenses
This page lists the copyleft licenses that we recommend free software projects and associated documentation use.
Software licenses
- The GNU General Public License, version 3 or any later version
- The GNU Affero General Public License, version 3 or any later version
Documentation licenses
- The GNU Free Documentation License, version 1.3 or any later version
To learn more about when and why we recommend these licenses, please see How to choose a license for your own work. Note that only the licenses listed above are recommended copyleft licenses; other licenses discussed in that guide are not copyleft licenses, or else suggested for use in more narrow circumstances.
This page is maintained by the Free Software Foundation's Licensing and Compliance Lab. You can support our efforts by making a donation to the FSF.
You can use our publications to understand how GNU licenses work or help you advocate for free software, but they are not legal advice. The FSF cannot give legal advice. Legal advice is personalized advice from a lawyer who has agreed to work for you. Our answers address general questions and may not apply in your specific legal situation.
Have a question not answered here? Check out some of our other licensing resources or contact the Compliance Lab at licensing@fsf.org.