Interactive digital technologies pervade our shared spaces in personal, mobile, infrastructural and other embedded forms. These changes challenge the ways we understand and investigate the relationships between people, computing and settings. Responding to this situation-where ubiquitous computing is not only personal but also public, and where digital interactions may happen anywhere-this special issue explores how HCI research can use the strengths of an intersection of theory, practice and innovation in order to best address this conjunction of interactive technologies, public spaces and people interacting with or within both.With this shift to interaction happening in public spaces, people can no longer be seen as just 'users' but have to be understood as acting assemblages of bodies and technologies in the space they inhabit. This shift highlights the need to understand users in every setting-including those at desks and at work-as socially and culturally situated humans with agency. While this is not a new research development, this special issue speculates on and discusses how the shift to 'everywhere interactions' makes it important for research in human-computer interaction to reach beyond existing conventions. With this work comes a need to understand the interacting human as a situated body that is at any moment also a possible spectacle: as a body, a human and a user who engages with technology in response to the situation while also being a 'performance' for others to witness. Understanding people as actors in their context allows us to regard every user as a 'performing body' and a 'performing subject', and it enables us to analyse the performative aspects of interaction in many other situations than those where we design for actually staged performances in a defined performance space or stage. In this sense, 'performative interaction' is both concerned with technologies for on-stage performers using technologies as part of artistic expression, and an analytical frame for understanding every situation in which people engage with technologies (in public space). The question becomes: where and in which situations is this analytical frame relevant and useful?Recognising a growing interest in the HCI community to work with ubiquitous computing as a personal but also public technology, the editors set out to explore a number of topics within performative interaction that would develop and possibly consolidate contemporary work into a nuanced perspective on human-computer interaction in public space. Partly based on previous work with these questions, we selected contributions that expand our understanding of performative interfaces in a variety of settings as well as demonstrate ways of participating in performative interaction, of developing techniques for hiding and showcasing different elements of performance and of evaluating the experience of performing in public.