Extracellular vesicles (EVs)are a group of cell-derived membrane vesicles that carry a variety of cargo such as protein, nucleic acids, andlipids, and are secreted by almost all cell types. Functionally, EVs play important roles in physiological andpathological processes such as immune responses and tumor growth through intercellular communication bytransferring this molecular information between cells. Therefore, they have potential versatile clinical applicationsas disease biomarkers and drug delivery carriers. Notably, subpopulations of EVsexhibit distinct characteristics depending on their cell of origin, including the expression of surface glycans, whichhave been implicated in a variety of cellular processes such as field cancerization, cell recognition, and signaltransduction. However, these are features have not been fully exploited because of the difficulty in analyzing theseproteins. In this paper, we summarize the advancements in glycoengineering andhigh-performance lectin microarray for high-throughput analysis of EV glycans to generate an index ofheterogeneity to identify disease biomarkers, and describe how understanding the function of EVs in disease canenhance their potential application in the clinic.