We address the interrelationships between social and ecological outcomes of environmental policies and programmes under different modes of governance. While environmental policy often produces unexpected social side effects, both positive and negative, policy-makers and scholars have also long recognised potential synergies in combining social and environmental policy goals. With reference to collaborative environmental governance, such as in the case of the European Water Framework Directive, we examine the identification of community participation as a tool for achieving environmental objectives, and consider the implications of this for environmental policy and programme evaluation. We draw attention to the importance of social outcomes both as intermediary goals instrumental in securing environmental outcomes, and as potentially significant in their own right. The instrumental value of socially inclusive modes of governance and decision-making is apparent insofar as participatory approaches have been shown to increase (albeit in contingent ways) the legitimacy and acceptance of policy process and the effectiveness of outputs. Furthermore, participatory modes of environmental governance may yield significant extra-environmental benefits for communities of stakeholders and participants, through fostering new or existing networks, enhancing social capital, or up-skilling, educating or otherwise empowering individuals or groups. While the particular social-ecological consequences of more or less participatory approaches to environmental governance are highly context dependent, we argue that they are deserving of central consideration in the framing of environmental policy evaluation. In addressing the above themes, we draw on our on-going work on the European Research Council-funded project EDGE (Evaluating the Delivery of Environmental Governance using and Evidence-based Research Design).