The primary RTEMS source image is a collection of software that is licensed under a variety of free and open source licenses appropriate for use in embedded systems. The common characteristic of all of these licenses EXCEPT the GoAhead Webserver License is that they allow linking with no requirements placed on the end user application. The following licenses apply to the various components.

• Primary RTEMS License which covers most of the source code in RTEMS
• TCP/IP Stack License
• RPC/XDR License
• GoAhead Webserver License (requires graphic to be displayed on website hosted)
• Stanford University Permissive License