Plastic pollution in aquatic ecosystems is a growing environmental concern, as it has the potential to harm ecology, imperil aquatic organisms and cost ecological damage. Although rivers and other freshwater environments are known to play an important role in carrying land-based plastic trash to the world's seas, riverine ecosystems are also directly impacted by plastic pollution. A detailed understanding of the origin, movement, fate, and effects of riverine plastic waste is critical for better quantifying worldwide plastic pollution transport and effectively reducing sources and dangers. In this review, we emphasize the current scientific state of plastic debris in rivers, as well as the existing knowledge gaps, providing a basic overview of plastics and the types of polymers commonly found in rivers and the threat they bring to aquatic ecosystems. We also go through the origins and fates of riverine plastics, as well as the mechanisms and factors that affect plastic debris transit and spatiotemporal variation. We give an overview of riverine plastic transport monitoring and modeling activities, as well as examples of typical values from throughout the world. Finally, we discuss what the future holds for riverine plastic research.