ExpressionEngine Alternatives for PHP

October is a free, open-source and self-hosted content management system written in PHP on top of the framework Laravel. The CMS features a universal extendable dashboard, inspector, reusable CMS components and a plugin system that can be used to extend functinality of your website. The plugin store contains thousands of community-made plugins that can either be purchased or installed for free. As a data store, October CMS supports MySQL, PostgreSQL and SQLite.

PyroCMS is a free and open-source Content Management System written in PHP on top the web development framework Laravel.

MODX is a free, open source content management system and digital experience platform. The CMS gives you full control over your creative, editorial vision and the experience you deliver. MODX is written in the programming language PHP and supports both MySQL and Microsoft SQL Server databases. The CMS is openly developed and released under the GPL license, and allows contribution.

Joomla is a free and open-source content management system written in PHP. The CMS is built entirely by volunteers from all over the world and has a strong community that provide educational resources, and extensions. 

CMS Made Simple is a free and open-source content management system that offers an easy to use interface for end users, while maintaining a powerful backend for developers. CMS Made Simple is written in PHP and got an extensive API and custom modules. The CMS also utilize the Smarty templating engine that can be used to customize sites with HTML, CSS and PHP.

TYPO3 is a free and open-source content management system written in PHP. The CMS is released under the GNU General Public License which makes it free to use for commerical and non-commercial projects alike. TYPO3 can run in most hosting environements and provides an easy way for people to write, manage and publish content online.

Drupal is a free and open-source CMS written in PHP. Drupal is used for creating website for businesses, political parties and governments. The CMS currently powers 2% of all websites on the internet.

WonderCMS is the smallest flat file content management system. The CMS is built with PHP and has been developed since 2008. No initial configuration required to setup the WonderCMS, the installation is straight forward and simply requires you to unzip and upload 5 files.All data within WonderCMS is structured as JSON format and the flat file nature of the content management system also allow you to migrate hosts easily by transfering files across, no database migration required.

Fork CMS is a free and open-source, easy to use content management system built with PHP and Symfony Components. The content management system features an intuitive administration panel that makes it easy to create and manage content for the web. Fork CMS also comes packed with apps that can be installed to extend the feature set of the content management system.

Exponent CMS is a notable free and open source content management system that contains its own independent modular software framework of enterprise level.

Quanta is a free, open source Content Management Framework thought for programmers and used for the creation of new-generation websites and applications.