Background: Despite national and international policies to develop social capital in disaster-affected communities, empiric evidence on the association between social capital and disaster mental health is limited and ambiguous. Objective: The study explores the relationship between social capital and disaster mental health outcomes (PTSD, anxiety, and depression) in combination with individual factors (appraisal, coping behavior, and social support). Design: This is a community-based cross-sectional study in a flood-affected town in northern England. The study is part of the MICRODIS multi-country research project that examines the impact of natural disasters. It included 232 flood-affected respondents. Results: The findings showed that a considerable part of the association between cognitive and structural social capital and mental health is exerted through individual appraisal processes (i.e. property loss, primary and secondary appraisal), social support, and coping behavior. These individual factors were contingent on social capital. After the inclusion of individual characteristics, cognitive social capital was negatively related to lower mental health problems and structural social capital was positively associated to experiencing anxiety but not to PTSD or depression. Depression and anxiety showed a different pattern of association with both components of social capital. Conclusions: Individual oriented stress reducing interventions that use appraisal processes, social support, and coping as starting points could be more effective by taking into account the subjective experience of the social context in terms of trust and feelings of mutual support and reciprocity in a community. Findings indicate that affected people may especially benefit from a combination of individual stress reducing interventions and psychosocial interventions that foster cognitive social capital.