Embodiments of the invention provide a novel and non-obvious method, system and computer program product for generating a document taxonomy based upon tag data in groupings of tags. In an embodiment of the invention, a method for generating a document taxonomy based upon tag data in groupings of tags has been claimed. The method includes retrieving into memory of a host computer different groupings of tags for correspondingly different documents providing a bottom-up view of the documents. The method further includes deriving a folksonomy from the groupings of tags for the documents and organizing the folksonomy into a hierarchy of nodes. Of note, each of the nodes can be associated with a different subject in the folksonomy. Finally, the method includes publishing the hierarchy of nodes as a taxonomy for the documents to provide a top-down view of the documents.