Hydration may refer to:

• Hydrate, a substance that contains water
• Hydration enthalpy, energy released through hydrating a substance
• Hydration reaction, a chemical addition reaction where a hydroxyl group and proton are added to a compound
• Hydration shell, a type of solvation shell
• Hydration system, an apparatus that helps its user drink enough liquid while engaged in physical activity
  • Hydration pack, a type of hydration system composed of a carry-on pack used for hydration
• Mineral hydration, an inorganic chemical reaction where water is added to the crystal structure of a mineral
• Drinking in general, including:
  • Fluid replacement, the medical practice of replenishing bodily fluid
  • Oral rehydration therapy, hydration as a health treatment
  • Management of dehydration, medical hydration
• Tissue hydration, the supply and retention of adequate water in biological tissues
• Water of hydration, water that occurs within crystals
• Hydration (web development), the preparation of web page content for user interaction.
• Dough hydration, the percentage of water in a dough in relation to the amount of flour

• Dehydration (disambiguation)
• Solvation