Introductory remarks on the role of stakeholders in addressing plastic pollution of the aquatic environment.- Human perceptions and behavior determine aquatic plastic pollution.- Society role in the reduction of plastic pollution.- Education against Plastic Pollution: Current Approaches and Best Practices.- Stakeholder analysis in solving the problem of accumulation of plastics in surface waters of protected areas.- The role of policy in tackling plastic waste in the aquatic environment.- Monitoring approaches for marine litter in the European Sea basins.- Plastics in the Austrian stretch of the Danube River - From environmental data to action plans at the local, national and international level.- Plastics in freshwater: a new challenge for the International Commission for the Protection of the Rhine (ICPR)?.- Five years since the 2013 HELCOM Ministerial Declaration.- Combating marine plastics: the role of finance and technical assistance by Development Finance Institutions.- The current state of law on plastic pollution in Mexico and a view towards the future.- The problem of microplastics and regulatory strategies in Italy.- Concluding remarks on the role of stakeholders in addressing plastic pollution of the aquatic environment.