Mass collaboration is a form of collective action that occurs when large numbers of people work independently on a single project, often modular in its nature. Such projects typically take place on the internet using social software and computer-supported collaboration tools such as wiki technologies, which provide a potentially infinite hypertextual substrate within which the collaboration may be situated.

A key aspect which distinguishes mass collaboration from other forms of large-scale collaboration, is that the collaborative process is mediated by the content being created - as opposed to being mediated by direct social interaction as in other forms of collaboration.