Managing numerous websites can present challenges in keeping track of multiple administrator logins, often compromising security. Implementing single sign-on (SSO) simplifies this process, and FusionAuth SSO offers a streamlined solution for accessing multiple sites securely with a single set of credentials. This tutorial details integrating FusionAuth with Joomla, a popular PHP-based content management system, to enable OAuth SSO, allowing users to log in once and seamlessly access multiple applications. The process involves setting up a FusionAuth account, configuring an OAuth plugin for Joomla, and adjusting settings to ensure secure and efficient user authentication. FusionAuth not only supports OAuth but also accommodates complex standards like OpenID Connect and SAML, making it a robust tool for identity and access management. The guide further explains how to configure user accounts, set up login buttons, and troubleshoot common issues, ultimately enhancing user management and access control for Joomla site developers.