TWiki is an enterprise collaboration platform and knowledge management system. It is a structured wiki, typically used to run a project development space, a document management system, a knowledge base, or any other groupware tool, on an intranet or on the internet. Web content can be created collaboratively by using just a browser. Users without programming skills can create wiki applications. Developers can extend the functionality of TWiki with plugins.

TWiki enables simple form-based web applications, without programming, and granular access control (though it can also operate in the classic 'no authentication' mode). Other enhancements include configuration variables, variable text, transclusion, email notification, embedded searches, server-side includes, file attachments and a plugin API that has spawned over 240 plugins to link into databases, create charts, tags, sort tables, write spreadsheets, create image gallery and slideshows, make drawings, write blogs, plot all kinds of graphs, interface to many different authentication schemes, track Extreme Programming projects and so on.

TWiki is fully skinnable in both templates, themes and (per user) css, and can be used to create modern-looking wiki sites. It includes reasonably good support for internationalization ('I18N'), with support for UTF-8 URLs and support for UTF-8 content. The ease of its revision control and the availability of access control lists makes TWiki especially suited for enterprise and corporate wiki sites. The user interface has been translated into several languages, currently Chinese, Danish, Dutch, French, German, Portuguese, Spanish, Italian, Polish and Swedish.

TWiki is implemented in Perl and is Free and Open Source Software licensed under GPL. It is also available as a virtual appliance.