Introduction: Promoting inclusive, safe, resilient, and sustainable communities is one of the 17 Sustainable Development Goals ratified in 2015 by 193 UN member states, not least in Sweden. Social sustainability involves preserving particular societal values (e.g., local identity) as well as developing values (e.g., social cohesion) that are perceived as needed. Socially sustainable development also implies promoting integration and preventing segregation. Social capital is one important indicator to measure how socially sustainable an area is. This project aims to explore how social capital can be used as a conceptual tool in developing housing policy for social sustainability in Umeå Municipality. Methods: The three sub-studies in this project combine quantitative and qualitative methods. We will conduct a review of the municipality's documents to understand how the ideas of social sustainability have influenced political declarations and implemented social and housing policies and interventions during the period 2006-2020. The quantitative study includes a longitudinal follow-up to the 2006 survey's respondents to assess the longitudinal impacts of neighborhood social capital on health and well-being; as well as a new repeated cross-sectional survey to investigate how social capital has changed in local neighborhoods from 2006 to 2020. The qualitative study includes case studies in neighborhoods with different social capital dynamics to understand how different resident sub-groups perceive their neighborhoods and how implemented social and housing policies have influenced the social capital dynamics and responded to the needs of different sub-groups. The project is run in close collaboration with the Commission for a Socially Sustainable Umeå. Discussions: This project will create new and unique perspectives on long-term structural changes of relevance for a socially sustainable housing policy; knowledge that is highly valuable for continuous municipal planning; and will outline recommendations to guide local housing policies for social sustainable neighborhoods in Umeå Municipality. Ethics: This study has been assessed and approved by the Swedish Ethics Review Authority (Dnr: 2019-04395; Dnr: 2020-00160; Dnr 2020-02757). Dissemination: The dissemination goals of this project are (1) sustained engagement of key stakeholders throughout the project and (2) dissemination of the research findings through popular science, conferences, and scientific papers.