This paper aims to evaluate the situation of dumping grou-nds in some regions of the world and to size its impact on the expecta-tions of the European Union (EU) to achieve sustainable development. It traces intersections of international trade theory, European law, and the principle of sustainable development with the practice of major global players, focusing on the EU. The dumping grounds in third countries gi-ves room for questioning the opportunities and threats that the Europe-an block faces to achieve environmental sustainability and how the very countries of Europe, as importers and exporters of fast-fashion clothes are co-responsible for the environmental drama faced by other coun-tries that deal with these products, which become waste. The purpose of this research is therefore to analyze the effectiveness of the principle of sustainable development in the final stage of the production chain of fast-fashion clothing, seeking to bring an analysis centered on interna-tional and European law. As for the research method adopted here, it is developed through bibliographic and documental analysis and a case study. The development of the work is divided into three chapters. The first seeks to compare environmental conventions on the subject. The second chapter analyzes the production cycle of fast-fashion clothing, the countries and entities involved, and the accentuated waste produc-tion in a panorama of international transactions. The last chapter seeks to examine the actions of the EU to curb similar practices, where there is accountability in the European and international market for damages committed to the environment also in third countries. It concludes that there is a possible European success in enacting a due diligence directi-ve with a specific scope to curb market practices that continuously pro-duce products and exempt themselves from responsibility for their final destination, thus disregarding the sustainability of the environment.