This report aims to enhance understanding of the implications, capacity needs and enabling conditions for trade liberalization of environmentally sound technologies (ESTs), with focus on developing countries. It focuses its analysis on five ESTs, namely solar photovoltaic cells (PVs), water filters, waste incinerators, gas filtering machinery, hemp and flax fibers. To do that, the study takes a holistic approach and combines trade flow analysis with policy research. It draws upon findings from two regional assessments on EST trade in the Association of Southeast Asian Nations (ASEAN) and the East African Community (EAC), including country case studies in Malaysia and Kenya. Data was collected from multiple sources, including the United Nations Comtrade database, the World Trade Organization (WTO) database on trade in services, country- and company-level data, as well as scientific publications.