Overconsumption and mismanagement of plastic, particularly single-use plastic, is a growing menace across the globe and it has become an emerging contaminant for terrestrial as well as aquatic ecosystems challenging their sustainability. Owing to the characteristics of lightweight and high durability, plastic materials have the potential to be transported across long distances from their source without any degradation and finally deposited in lentic or lotic ecosystems. Out of the global production of 300 million metric tons/annum of plastic waste, approximately 0.8–30 million metric tonnes, finds its final destination in the aquatic environment annually. The predominant source of plastic pollution is terrestrial, with its transportation occurring primarily through the rivers/canals and ultimately leading to the contamination of near-shore sediments as well as the marine environment. In the end, plastic products find their way into the food chain, creating a grave threat to the well-being of aquatic life forms and their consumers. The primary contributors to this extensive accumulation of plastic waste include a deficiency in technical expertise, inadequate infrastructure development, and, most importantly, a lack of user awareness. The present chapter provides an overview of plastic and microplastics; their sources; pathways to the aquatic systems and their detrimental impact on human health and other terrestrial and aquatic biota, along with the comprehensive mitigation strategies employed to address this issue of global interest. This chapter also delves into some treatments available to mitigate plastic pollution including physical, thermal, chemical and biological, as well as advanced techniques like membrane-based technologies and advanced oxidation processes. Implementation of plastic waste management practices like the Circular Economy approach, 4R’s principles, adoption of Extended Producer Responsibility (EPR) etc. which can indirectly reduce the plastic load of the aquatic ecosystems, and possible environmental-friendly plastic pollution-reducing strategies are also discussed.