The findings from this study intend to provide an important basis for launching effective plastic pollution management and control measures in global countries. Marine plastic debris is mainly derived from land-based sources, and the transport of plastics via global rivers is of great concern. India, China, and Indonesia are the top three contributors to riverine plastic outflows, whereas Guatemala, the Philippines, and Colombia have the highest per capita riverine plastic outflows. Population, plastic waste generation, and the Human Development Index are the dominant factors influencing riverine plastic outflows to global oceans from individual countries.