International law divides global ecological issues into different categories of harm depending on the spatial dimensions of the problem. This chapter explores the problem of transnational ecological harm, that is, cases where despite the “activity and physical damage” all occurring within a single host state, there is a clear “transnational involvement” due to the export of capital from a state of origin or home state. While the work of scholars who draw upon the natural law tradition would support home state obligations to protect intra-territorial ecological integrity of host states, reliance upon the natural law tradition is troubling due its history as a tool used by colonial powers to suppress the uncivilized “other”. This chapter explores whether insights from scholars who adopt Third World Approaches to International Law (TWAIL) could serve to supplement a natural law analysis of transnational ecological integrity problems.