Knee osteoarthritis (KOA) is a degenerative disease characterized by degeneration of articular cartilage. So far, there is no effective drug to treat KOA. Extracellular vesicles (EVs) are spherical membranous vesicles formed by the envelopment of lipid bilayers released from cells, which can deliver bioactive molecules such as nucleic acids and proteins between cells. Mesenchymal stem cell derived EVs can be used as an effective way in KOA treatment by reducing inflammation and promoting cartilage repair. Compared with mammalian-derived EVs, plant-derived EVs have attracted much attention in the field of drug carrier delivery research because of their wide and economical sources. It is worth noting that vesicles derived from Chinese herbal medicine have great prospects in disease treatment. Modification of EVs for drug delivery by genetic engineering and other methods can greatly improve drug delivery efficiency and its efficacy. In addition, the hybrid vesicles prepared by membrane fusion can efficiently deliver CRISPR/Cas9 plasmids for KOA treatment. Because of its diversified functions and modifiability, EVs have great prospects in disease treatment and drug delivery. This paper reviews the progress of EVs from animals and plants in the treatment of KOA, focusing on the research and development of engineered EVs as drug delivery carriers in KOA treatment, in order to provide a reference for the use of EVs in the treatment of KOA.