AbstractIncreasing research has been devoted to examining collaborations between public and private actors in environmental regulation under neoliberal democracies. However, this public-private interaction in authoritarian regimes remains understudied. This article seeks to address this gap in the literature through an empirical examination of the interaction between environmental non-governmental organizations (NGOs) and procuratorates in China's environmental public interest litigation. We find emerging complementarity: NGOs focus on new issues and target high-profile defendants to increase the socio-legal impact of their civil litigation, whereas procuratorates increasingly engage in administrative litigation against government agencies. This complementarity is shaped by the different legal opportunities for Chinese NGOs and procuratorates, as well as their respective institutional objectives and capacities. Their divergent regulatory preferences have also fostered synergy between these two actors, allowing them to collaborate on legal experimentation and innovation.