Encouraging pro-environmental behavior is an urgent global challenge. An interdisciplinary framework covering governance, economic, social, ecological, and psychological dimensions is required to understand the salient features that encourage pro-environmental outcomes within and across contexts. We apply the Ostrom social-ecological systems framework to model voluntary investments by members of civil society into the aquatic environment. Using a data set of 1,809 angling clubs managing water bodies for fish stocking and habitat management in Germany and France, we show that a small set of factors, most crucially social-ecological and governance context as well as social norms and other bottom-up social pressures, drive environmental investments. These factors appear to override behavioral influences from psychological variables of the decision-maker. By contrast, the contextual setting related to property rights, size of the resource system, and social expectations were found to be strongly related to behavioral decisions, highlighting that the social-ecological context as well as incentives may be more important than knowledge and cognitions in driving certain pro-environmental actions