FCK may refer to:
- F.C. København (F.C. Copenhagen)
- 1. FC Kaiserslautern, a German football club based in Kaiserslautern, Rhineland-Palatinate
- FCKeditor, a WYSIWYG web text editor (created by Frederico Caldeira Knabben)
- Free Collars Kingdom, a Japanese manga series
- Former Chairman King, boss in Okage