Pages in this category should be moved to subcategories where applicable. This category may require frequent maintenance to avoid becoming too large. It should directly contain very few, if any, pages and should mainly contain subcategories.

This category contains operating systems that are described as "free software" or "open-source software". There are multiple licenses possible for both types; licenses that specify what can and cannot be done with the software.

Wikimedia Commons has media related to Free software operating systems.