Social capital, defined as trust, reciprocity, rules, norms, sanctions and networks, has many applications in the management, adoption and acceptance of sustainability certifications. On an individual level, generalized trust in others has been shown to be an important predictor of an individual's participation in voluntary environmental programs and on public-good contributions. On the organizational level, social capital, considered a public good, effects organizational learning, management and collective action. To better understand the link between social capital and sustainability certifications, we conducted case studies of four Costa Rican coffee cooperatives with supplementary interviews with administrators at two additional cooperatives. We used a mixed-methods approach consisting of qualitative interviews with cooperative administrators and quantitative household surveys. Social capital of the cooperatives was assessed in six dimensions: groups and networks, trust and solidarity, collective action and cooperation, information and communication, social cohesion and inclusion and empowerment and political action. We applied this information to its effects on the management of sustainable coffee certifications. We found that the level of these six dimensions of social capital affected the manner in which cooperatives manage certifications, incentivize certified members and cooperate with outside organizations. On an individual level, generalized trust was found to have an important link with voluntary participation in environmental certifications when no financial incentive was provided. Strategies for managing certifications and other programs have the potential to build social capital in cooperatives. This research has important implications for the management of certifications and other similar schemes such as payment for ecosystem services and participatory guarantee systems. (Texte intégral)