Open educational resources, like all intellectual property, are subject to the laws of copyright. But some creators would rather share their work than reserve all of their rights for themselves. Creative Commons has created tools that allow creators of copyrightable work the ability to do this within the framework of copyright laws as they exist now. Creative Commons licenses are real, legal licenses that help creators retain copyright while allowing others to copy, distribute, and make some uses of their work.
The Choose a License Tool provides an easy way for creators to define the terms on which others may use their work.
This page shows the best way to give attribution for a Creative Commons licensed work.
OER may also be used from the public domain (works for which copyright has expired), fair use (such as using small parts of works for educational purposes), or library resources (when you are able to direct your students to use a library resource instead of having them buy it).
For more details on the way OER works within copyright, see the Copyright, Fair Use and Licensing for OER module.