This report presents findings of capacity-mapping study on the monitoring and assessment of plastic pollution in the Lower Mekong Region. The study was conducted as part of the UN Environment Regional Office for Asia and the Pacific's project titled the *Promotion of ConterMEASUREs against Marine Plastic Litter in Southeast Asia and India" (hereafter, referred to as * ConterMEASURE project"). The CounterMEASURE project aims to develop a region-based approach for the monitoring and assessment of land-based plastic waste leakage and for pollution reduction into inland water ways, such as rivers, canals and drainage systems, and the eventual transport of plastic waste into the oceans.