While the detrimental impacts of plastic pollution have long been acknowledged, systematic investigation into the occurrence, ubiquity, and ecotoxicological consequences of microplastics – defined as plastic particles smaller than 5 mm – has only gained momentum in more recent years. Considerably less attention, however, has been devoted to the role of these particles as vectors for diverse chemical constituents, including not only both additives intentionally or unintentionally incorporated during plastic manufacture, but, perhaps more importantly, organic pollutants already present in the environment that are sorbed by these particles. Given the pervasive distribution of microplastics across all environmental compartments and the heterogeneity of their physicochemical properties, elucidating the mechanisms governing the uptake and release of associated compounds remains inherently complex. Nevertheless, such understanding is essential to accurately evaluate the combined impacts of microplastics and sorbed chemicals on ecological systems. In this chapter, the processes and factors influencing these interactions, with particular emphasis on the ecological implications of chemical sorption to microplastics, are examined. Furthermore, the critical limitations in the current body of literature are highlighted, and a forward-looking perspective on future research directions in this field is suggested.