Dehydrins are highly hydrophilic proteins that accumulate during embryogenesis and water stress responses in plants. Although dehydrins were discovered in the 1980s, their physiological functions are unknown. However, recent molecular-based studies have provided insights into the multifunctionality of dehydrins. The functional versatility of dehydrins is reviewed using recent experimental evidence, and perspectives in the functional studies of dehydrins are also discussed.