Joomla Single Sign-On (SSO) is an authentication process in which a user can login to multiple applications and/or websites by using only a single set of login credentials (such as username and password). This prevents the need for the user to login separately into the different applications. Joomla Single-Sign-On addresses the challenge of maintaining the credentials for each application separately, streamlining the process of signing on without the need to re-enter the password.