This thesis aims to improve the understanding of bonding, bridging and linking social capital in Malawi and how they relate to food security and sustainable development. The gender and spatio-temporal differences that influence how social capital typologies are associated with food security and sustainable development are also considered. There is limited research that focuses on low-income countries or unpacks social capital into its bonding, bridging and linking social capital. Similarly, despite an acknowledgement that social capital, food security and sustainable development are influenced by gender and spatio-temporal variations, research is lacking that synthesises the concepts. Social capital’s link with food security is not properly understood due to the complexities of both concepts. Despite social capital being a potentially useful mechanism for improving food security, and sustainable development more broadly, the lack of research is a barrier to its inclusion in development policies and projects.This thesis employs quantitative and qualitative methods including regression modelling, spatial statistics, geographic information systems and rapid rural appraisals. The thesis has four broad findings. Firstly, bonding, bridging and linking social capital varies spatially across Malawi and diverges from the social capital that is expected in low-income countries. Secondly, social capital’s association with food security and sustainable development outcomes differ by gender of household head and by the social capital typology. Thirdly, gender differences exist in how social capital is used to access food, which links with broader gender inequality. Finally, there are long- and short-term differences in how bonding, bridging and linking social capital is used to access food, suggesting the typologies of social capital are interlinked and dynamic. This thesis provides sustainable development policymakers and practitioners with an improved understanding of the complexities of social capital in a low-income country and how it is associated with food security and sustainable development, whilst accounting for gender and spatio-temporal variations.