The past 30 years have seen England's housing associations (HAs) transformed from marginal players in the wider housing market to a point where, in 2008, they overtook local authorities as majority social housing providers. This paper reviews theoretical perspectives on the evolution of the UK social housing and the rise of HAs since the 1970s, with a particular focus on the â€˜modernisationâ€™ thesis advanced by Malpass Victory (2010). Against this backdrop, we analyse the sector's recent reconfiguration, integrating the impacts of housing stock transfers and HA mergers. Our analysis focuses on the consequences of sector restructuring in terms of organisational homogenisation and, at least as perceived, the growing dominance of giant landlords. Finally, within the context of the Coalition Government's localism rhetoric, we discuss the accountability implications of restructuring activity and the light our analysis sheds on theoretical understandings of social housing change processes.