Extracellular vesicles (EVs) are fundamental mediators of cell-to-cell communication under physiological and pathological conditions. They are double-membrane vesicles carrying bioactive proteins, genetic materials, and lipids, the majority of which are in common with the originating cells. EVs display the capacity to transfer bioactive molecules and genetic information to target cells, influencing their behavior. EVs can be classified based on their size, origin, biogenesis or cargo or function, and can be divided into different categories. In this chapter, EV discovery, classification, and biogenesis will be summarized. Moreover, present and future clinical applications of EVs are presented. Convincing evidence highlights the regenerative potential of stem cell–derived EVs for several disease models. Stem cell–derived EVs recapitulate the properties of the originating cells and could be considered innovative therapeutic tools for clinical application.