Social capital is widely recognized as health bolstering and more recently as playing a central role in family and community disaster response and recovery. Community social institutions may be considered a critical mechanism for the development of social capital, as they provide opportunities for community members to interact to build the networks and relationships that are necessary for taking collective action. In particular, social institutions may have a pivotal role to play in supporting children's health and welfare postdisaster. Community social institutions such as membership, civic, and religious organizations are community resources that stimulate learning and foster healthy child development. This study explores communities impacted by Hurricane Katrina and the Deepwater Horizon Oil Spill (DWHOS). Social institutions data were paired with household interviews from the Women and Their Children's Health Study (n = 521) to explore whether the density and type of community social institutions in the community were associated with child mental health outcomes. Multilevel logistic regression models examining the role of social institutions, household characteristics, maternal characteristics, and child-specific factors in child mental health showed that for each additional prosocial institution established in the community during recovery from Hurricane Katrina, respondents were 21% less likely to report a child mental health diagnosis (odds ratio 0.79; 95% confidence interval 0.63-0.98). These findings highlight the potential of investment in social institutions in communities to bolster resilience and foster meaningful recovery.