Red Hat Enterprise Linux is a Linux distribution produced by Red Hat and targeted toward the commercial market, including mainframes. Red Hat commits to supporting each version of Red Hat Enterprise Linux for 7 years after its release. All of Red Hat's official support, all of Red Hat's training and the Red Hat Certification Program center is on the Red Hat Enterprise Linux platform. Red Hat Enterprise Linux is often abbreviated to RHEL, even if Red Hat is now attempting to discourage this.
New versions of Red Hat Enterprise Linux are released every 18 to 24 months. When Red Hat releases a new version of Red Hat Enterprise Linux, customers may upgrade to the new version at no additional charge as long as they are in possession of a current subscription (i.e. the subscription term has not yet lapsed).

Red Hat's first Enterprise offering (Red Hat Linux 6.2E) essentially consisted of a version of Red Hat Linux 6.2 with different support levels, and without separate engineering.

The first version of Red Hat Enterprise Linux to bear the name originally came onto the market as "Red Hat Linux Advanced Server". In 2003 Red Hat rebranded Red Hat Linux Advanced Server to "Red Hat Enterprise Linux AS", and added two more variants, Red Hat Enterprise Linux ES and Red Hat Enterprise Linux WS.

Verbatim copying and redistribution of the entire Red Hat Enterprise Linux distribution is not permitted due to trademark restrictions.[2] However, there are several redistributions of Red Hat Enterprise Linux minus trademarked features (such as logos and the name).