This chapter considers the issue of law enforcement responses (LERs) to transnational environmental crime (TEC) with a particular focus on the role of environmental regulatory agencies. The range of operational and policy factors which inform and shape their enforcement responses. It describes furnish environmental regulatory agencies with information, options, and strategies to more effectively detect, deter, and disrupt TEC. This research has particular relevance for environmental regulatory agencies, because, like all public service agencies, they seek efficiencies and effectiveness. This extends to and includes staff involved in environmental compliance and enforcement. The chapter highlights some of the difficulties arising due to the interaction between the different types of agencies undertaking environmental regulation and enforcement. Some difficulties present as a result of agency identity and preferences. It recommends an evidence and harms-based responsive and adaptive approach with clearly determined and pursued outcomes. Achieving this requires building and combining capability within and across environmental regulatory agencies and response agencies of all types.