<p>Microplastics are emerging pollutants in riverine ecosystems, causing significant environmental issues due to their ecological and socioeconomic impacts. To date, extensive research has primarily focused on the marine environment, while freshwater microplastics have remained underexplored. Since rivers serve as a conduit for microplastics from land to ocean, the relevance of understanding the mechanism of fate and transport of microplastics in rivers is now recognised. This review provides an overview of microplastic pollution in global rivers and their source and routes of entry. It also examines the key processes that govern the transport and transformation of microplastics in rivers, including weathering, sinking, aggregation, retention, and resuspension. Additionally, the review highlights the interaction with pollutants and their role in ecotoxicological impacts and associated socioeconomic impacts. Furthermore, some advanced techniques used in fate and transport studies, mitigatory measures, research gaps, and future research directions are also discussed. By covering a wide range of aspects related to microplastics in rivers, this review attempts to establish a deeper understanding of the fate and transport of microplastics, guiding future studies and mitigation efforts.</p>