Online role-playing games are a form of entertainment in which players create characters and improvisationally perform scenes together within a digital virtual world. It has many theatre-like aspects, which raises the question of whether it is in fact a form of theatre. To answer that question, however, one must first have a definition of theatre – an issue with disciplinary consequences – and in this article Tobin Nellhaus develops a definition founded on social ontology, suggesting that theatrical performance, unlike other social practices, replicates society's ontology. From that perspective, online role-playing meets the definition of theatre. But its digital environment raises another set of problems, since embodiment, space, and presence in online role-playing are necessarily unlike what we experience in traditional theatre. Here, Nellhaus brings these three aspects of performance together through the concept of embodied social presence, showing how they operate in both customary theatre and online role-playing. Tobin Nellhaus is an independent scholar who was Librarian for Performing Arts, Media, and Philosophy at Yale University. He has published mainly on the relationship between theatre and communication practices, and on critical realist theory in theatre historiography. He is the General Editor of the third edition of Theatre Histories (London: Routledge, 2016), and the author of Theater, Communication, Critical Realism (New York: Palgrave Macmillan, 2010).