Wikimedia chapters are national or sub-national not-for-profit organizations created to promote the interests of Wikimedia projects locally, by members of the movement. Chapters are legally independent of the Wikimedia Foundation, entering into an agreement with the foundation following acceptance by the Affiliations Committee (formerly known as "Chapters Committee"), and have no control over Foundation websites. They organize regional conferences, outreach, and global events such as Wikimania.

Wikimedia Deutschland (WMDE) is the oldest chapter, holding its first meeting in 2004. As of 2016, it had a budget of €20 million. Some chapters such as WMDE get some of their funds directly from grants and supporting memberships. Some others get their funds primarily from annual plan grants from WMF. As of 2019, roughly 10% of the WMF budget is distributed in this way to chapters and thematic organizations. As of August 2019 there were 40 recognized Wikimedia chapters in 38 countries.