Drupal is a free open source content management system (CMS) and content management framework (CMF) written in PHP that allows you to easily publish, manage and organize a wide variety of content on a website. It is used as a back-end system by hundreds of thousands of people and organizations worldwide ranging from personal blogs to corporate, political, government, media & publishing, non-profit, schools and individuals' sites. It is also used for knowledge management and business collaboration.

The standard release of Drupal, known as Drupal core, contains basic features common to CMSs. These include user account registration and maintenance, menu management, RSS-feeds, page layout customization, and system administration. The Drupal core installation can be used as a brochure ware website, a single- or multi-user blog, an Internet forum, or a community website providing for user-generated content. Drupal runs on any computing platform that supports both a web server capable of running PHP and a database to store content and settings. Although Drupal offers a sophisticated programming interface for developers, no programming skills are required for basic website installation and administration.

Originally written by Dries Buytaert as a message board, Drupal became an open source project in 2001. Drupal is an English rendering of the Dutch word "druppel", which means "drop". The name was taken from the now-defunct website, whose code slowly evolved into Drupal. Drupal is distributed under the GNU General Public License, which means anyone is free to download it, share it with others, and contribute back to the project.