Digital tools for performance-assessment are commonly used to shorten the feedback loop in testing designs for buildings and neighbourhoods. However, these tools do not extend to the social dimension in the same way as the economic and environmental dimensions. This paper aims to contribute to the development of digital tools to design socially sustainable neighbourhoods. We analyse 115 academic articles to establish a theoretical understanding of Social Sustainability (SoSu). Based on these results, we propose a digital user-interaction model to operationalise SoSu in the digital design process of buildings. In the literature, we observe a lack of consensus on the theoretical discussion on SoSu. Several extrinsic and intrinsic factors are identified contributing to this fuzziness; the dependency on stakeholder value systems, the qualitative nature of social indicators, and comparison to environmental sustainability being the most common. Still, we distinguish two overarching categories, social equity and social capital, that are further divided into sub-themes. Having mapped the categories and hierarchies of social themes, we propose a user-interaction model that incorporates these findings into a digital environment. The user-interaction model creates a guided decision-making framework for architects and urban planners by enabling stakeholders to make conscious and informed decisions grounded in theory.