Although Communities of Practice have become a core concept in understanding how knowledge is managed within organizations, there have been few studies of the praxis of formation of Communities of Practice. In this article, we report on a Grounded Theory study of the members of a previously identified Community of Practice within the UK Higher Education Academy Psychology Network. In addition to providing data on the functioning of the community, the study also revealed a hitherto unrecognized form of community that exhibits all of the characteristics of CoPs yet has only a transient existence that seems to nucleate around an existing core community. Drawing on the metaphor of quantum behaviour, we termed these communities Quantum Communities of Practice. We describe a theory to explain this phenomenon that is grounded in the data from the study. We conclude by discussing the value and validity of our findings and methodology and indicating the next steps we will take in our research.