In war affected populations there is often severe disruption of societal cohesion. Additionally, grief and traumatisation, along with insufficient health services and a lack of security, give rise to an increase of mental health problems. Social capital is potentially a key resource to support post conflict recovery, and is increasingly considered not merely as a resource supporting economic and social development, but also an important influence on population health. However, linkages between social capital and mental health are complex. Therefore, this article begins with an introduction to the construct of social capital, then provides an overview of the main findings on its relation to health and wellbeing, as well to mental health in general and in post emergency situations. Finally, it explores if social capital may be promoted intentionally, as pursued through a community based sociotherapy programme in Rwanda. While there appears to be a rationale for promoting social capital within post conflict settings, further work is required, both documenting reliable means of securing it and disentangling pathways of influence on social wellbeing and mental health.