Resource and environmental managers are increasingly facing problems characterized by high degrees of ecological and social complexity, uncertainty and indeterminacy, and conflicts over values and interests. Moreover, they are often faced with the need to generate positive change in dynamic social-ecological systems. Comprehensive, rational management approaches have often failed to respond effectively to these types of problems. In response, policy makers and managers are increasingly relying on social learning approaches, i.e., adaptive and participatory approaches that facilitate learning by the individuals and organizations involved in resource and environmental governance. In this article, we examine social learning outcomes from the participation of two community organizations in the environmental assessment (EA) of a proposal to expand the Red River Floodway, a 48-km channel that diverts floodwaters around Winnipeg, Canada. The research design was a qualitative, comparative case study involving a review of documents, semi-structured interviews, and direct observation at meetings, open houses, and public hearings. The study findings demonstrate how EA public involvement processes can provide excellent opportunities for single-loop learning in community organizations. Through their involvement, the organizations in question deepened their knowledge, honed their skills, and made substantive contributions to the assessment process. The findings also suggest that public involvement processes can result in double-loop social learning conducive to sustainability. An important catalyst for the double-loop experience in this case was the provision of intervener funding. The findings also shed light on the organizational structure variables essential to create capacity for social learning in community organizations.