Social housing can play a large role for both the UK and global agenda to reduce greenhouse gas emissions. Political and industry efforts to promote sustainability in social housing in England are sparse, despite a plethora of existing research. One reason for this might be the lack of integration of different actors and elements in social housing. This study aims to fill this gap by developing a theoretical framework that can help different actor groups involved in social housing in England identify connections and transition to sustainability. The framework is developed and validated using a mixed methods iterative approach, including a Delphi study to begin with. Results are validated using interviews and document search and analysed by using discourse analysis. Results indicate that the social housing system consists of six actor groups who all have different interpretations of sustainability. External pressures on the system consist mainly of central government policies. Niche innovations have not broken through to the system yet. Powerful actors consist of the construction and finance industry, who influence central government in terms of policy making. Power is closely aligned with financialisation of housing. Comparing results to research on transition pathways for sustainability, no such transitions can be observed in the social housing system. This study represents a first attempt to develop a theoretical framework where social housing is conceptualised as a system, investigating its key change processes. Recommendations are defined for key stakeholder groups regarding the relevance of the framework to investigate pathways for a transition to sustainable housing.