Most OER are licensed using a Creative Commons license, which allows creators to choose exactly how their work can be used and reused. Since OER are not just free from cost but also have free and perpetual permission to engage in the 5 Rs (retain, reuse, revise, remix, and redistribute), it's important to tell others exactly how they can and cannot use the OER you've created. Similarly, if you're adopting existing OER or revising existing OER, you must understand how the licenses work so you know what you can and cannot do.
Creative Commons offers six main licenses that you can use to publish your work, four of which are appropriate for publishing OER. (Note: No Derivative Works licenses do not allow users to revise or remix and are therefore not appropriate for OER). The various licenses are listed below, starting with the most accommodating license type you can choose and ending with the most restrictive license type.
"CC License Freedom Scale Chart" by Foter, CC-BY-SA 3.0 Unported
Find out more about Creative Commons licenses, how to use them and how to interpret them, by consulting the following: