This special issue brings together new case studies and comparative works highlighting the drivers and dynamics of collaborative environmental governance. Each case is part of the Collaborative Governance Case Database, which is an open-access resource allowing individuals to contribute and access cases to support research projects. This article highlights the special issue’s contributions to collaborative governance theory. Common themes that cut across the studies include: the importance of using a broad definition of collaborative governance to capture the diversity in interorganizational relationships across contexts; improving our understanding of the drivers for initiating collaborative governance; an enhanced understanding collaboration’s lifecycle dynamics and developmental trajectories; the importance of individuals and their roles in collaborative processes; the political dynamics of collaboration; the role of accountability; and the challenges associated with assessing the performance of collaborations. Collectively, the cases also demonstrate the value of using resources such as the Collaborative Governance Case Database to undertake small-n and medium-n comparative studies that further theory building.