Microplastics (MPs), defined as plastic particles smaller than 5 mm, have emerged as a pervasive environmental contaminant in aquatic ecosystems. Their sources include primary MPs, manufactured at this size for commercial use, and secondary MPs, resulting from the degradation of larger plastic debris. MPs are ubiquitous in marine and freshwater environments, accumulating in sediments and being ingested by various aquatic organisms. The ecotoxicological consequences of MPs involve physical harm, chemical toxicity through adsorption of pollutants, and trophic transfer across food webs. MPs disrupt digestive processes, cause oxidative stress, impair reproductive functions, and act as carriers for persistent organic pollutants (POPs) and heavy metals. These pollutants bioaccumulate in aquatic organisms and can eventually impact human health through seafood consumption. Moreover, MPs affect ecosystem functions, reducing biodiversity and altering key ecological processes such as nutrient cycling. Addressing MP pollution requires an integrated approach, including pollution prevention, improved waste management, policy regulations, and public awareness campaigns to mitigate their impact on aquatic ecosystems and human health.