Rapidly growing, unregulated plastic litter has created a multitude of environmental and economic problems worldwide. With an estimated lifetime of centuries, plastic waste has become a major stressor in marine ecosystems. In West Africa, the use of plastic products has proliferated with urbanization, and their unregulated disposal has created a host of terrestrial and marine-related environmental problems. This study aims to help decision-makers better understand the economics of marine plastic-waste generation and its cleanup, with a focus on West African coastal countries. To aid the policy process to reduce marine plastic pollution, it addresses the following key questions: • What is the economic cost to society of marine plastic waste? • How does this cost compare with the pollution mitigation cost, using various incentive-based, command-and control approaches for pollution prevention and the cost of plastic waste removal through cleaning, recycling, and safe disposal? • Would general economic measures (for example, tariffs on imported polyethylene) significantly reduce pollution from single-use plastics? • Are there trade-offs between plastic pollution prevention and any other social objectives related to policymaking? How should cost-effective cleanups be implemented?