Numerous studies have been conducted on tumor biomarkers currently employed in cancer diagnosis, categorized according to the type of biomolecule targeted for detection [nucleic acids, (glyco)proteins, (glyco)lipids, glycans, metabolites, exosomes, etc.]. However, this section focuses primarily on glycans. The development of novel glycobiomarkers (glycan biomarkers) has the potential to profoundly impact the early detection and improve the prognosis of ovarian cancer. Moreover, advances in glycan analysis technologies are expected to facilitate their application in other malignancies and diseases. Research on glycobiomarkers offers exceptionally high disease specificity and contributes to elucidating the mechanisms of oncogenesis, pathophysiology, and tumor progression, thereby providing opportunities for the development of innovative therapeutic strategies.