Most research into sleep, even that which includes a sociological dimension, tends to focus on sleep outcomes, in effect following an agenda set by the natural sciences and psychology. The work reported in this paper engages with the material and social dimensions of sleep from within social constructionist and interactionist frameworks, seeking to explore and theorise the meaning and experience of sleep from the perspective of the sleeper. In doing this, we examine how contemporary constructions of sleep and constructions of childhood and adolescence arise and are linked in the UK context. Sleep time tends to be constructed as empty of activity other than sleeping and devoid of the sorts of interactions that characterise wakeful day-time. However, a grounded analysis of qualitative data generated with 9 children and 20 teenagers suggested that the assumption of absence of activity and interaction was misleading: their nights were populated by a range of actors, presences and activities. Placing our focus on these aspects of our participants’ accounts of their sleep we found that the temporal, spatial and interactional dimensions of routine sleep served to create a definable arena of action (Hutchby and Moran-Ellis 1998) which was marked out both materially and socially. We conceptually frame this arena of sleep as a night-world (Moran-Ellis, 2006).