A relationship between CSR and environmental law is intuitive; however, the nature, substantive content, and boundaries of the relationship remain unclear. This chapter explicates the relationship by examining the elements and ideas that shape it. It first considers the scope of CSR as a type of international private law, arguing that CSR does encompass environmental liabilities. It next reviews the earlier corporate environmentalism movement and its impact on CSR and environmental regulation. The chapter moves to consider the nature and scope of environmental law as primarily a domestic regulatory regime and what that entails as hard law. This approach is then contrasted with CSR’s international soft law focus and corollary regulatory approach of standards and reporting. After a discussion of the three main environmental principles—polluter-pays, prevention, and precaution—the chapter evaluates the relationship and its trajectory.