Tektins are important components of flagella. Alterations in the expression of or mutations in mouse tektins are correlated with defective sperm motility, a cause of male infertility. At the protein level, TEKT5 was present in sperm and was enriched in the accessory structures of flagella. Immunofluorescence confirmed that TEKT5 was localized throughout the sperm tail in flagellar accessory structures. The expression pattern suggests that TEKT5 plays an important role in flagella formation during spermiogenesis as well as being implicated in sperm motility.