AbstractWhile a majority of scholarship on the study of transnational advocacy networks (TANs) has focused on the role of value‐and‐belief‐sharing as these networks link activists across nations together, less has been written concerning the role of knowledge exchange among environmental nongovernmental organizations (ENGOs) in helping effect policy change. This article examines how transnational coalitions of ENGOs in North America have helped shape environmental policy across the Canada–U.S.–Mexico borders. In the paper, I explore two cases of nonstate actor mobilization: the North American Pollutant Release, and Transfer Registry Project and the Citizen Submission on Enforcement Matters. In this article, I bridge notions of "soft power" with scholarship on knowledge sharing, thereby showing that nonstate actors use it as a model to build stronger transnational coalitions, effecting pressure on industry and intergovernmental actors, and provide policy input in environmental decision making across borders.