Wikimedia Commons (or simply Commons) is an online repository of free-use images, sound and other media files. It is a project of the Wikimedia Foundation.

Files from Wikimedia Commons can be used across all Wikimedia projects in all languages, including Wikipedia, Wikibooks, Wikisource, and Wikinews, or downloaded for offsite use. The repository contains over 12 million media files.

The project was proposed by Erik Möller in March 2004 and launched on September 7, 2004. A key motivation behind the setup of a central repository was the desire to reduce duplication of effort across the Wikimedia projects and languages, as the same file had to be uploaded to many different wikis separately before Commons was created.

Given its primary function as a supporting project for the other Wikimedia web sites, the main content policy for files uploaded to Commons is that they must be potentially useful on any of the Wikimedia projects. This excludes material such as purely personal pictures and artwork, in contrast to image sharing repositories like Flickr, Photobucket and DeviantArt. Nevertheless, large numbers of files hosted on Commons are not used directly on any Wikimedia project and likely never will be; as such, the project has grown into a repository of multimedia in its own right, which is frequently linked to from articles on Wikipedia and other Wikimedia websites to provide supplemental materials.