Motivating individual contributions to and compliance with policies designed to provide and protect public goods is a major challenge for agri-environmental program administrators. This article investigates whether and to what extent stakeholder participation via anonymous, open-ended comments in the design and formulation of agri-environmental policy may motivate individual contributions to public goods and compliance with final rules and policies. We introduce a comment mechanism into a public goods experiment both with and without an exogenous enforcement mechanism to analyze the impacts on individual behavior. Stakeholder comments are found to have a large positive effect on both individual contributions to a public good and compliance with regulatory policies conditional on the presence of complementary enforcement. Stakeholder comments also significantly impact the behavior of policymakers, leading to higher contribution rules. We link our findings to the relevance of stakeholder inclusion for agri-environmental policymaking and potential to approach Pareto Optimal outcomes. Acknowledgement : We would like to thank Rachel Croson and Robert Myers for helpful comments on earlier drafts of this paper. We would also like to thank seminar participants at Michigan State University, and conference participants at AAEA 2017 and AERE 2017 for helpful comments. We gratefully acknowledge financial support for this project from the USDA-Economic Research Service and the Center for Behavioral and Experimental Agri-Environmental Research under grant 42734. SM also gratefully acknowledges support from the Global Center for Food Systems Innovation.