Hydration may refer to:
- Hydrate
- Hydration reaction, a chemical addition reaction where a hydroxyl group and proton are added to a compound
- Mineral hydration, an inorganic chemical reaction where water is added to the crystal structure of a mineral
- Solvation, the clustering of solvent (water) molecules around a solute particle
- Tissue hydration, the supply and retention of adequate water in biological tissues
- Water of hydration, water that occurs within crystals
- Hydration pack, a carry on pack used for hydration
- Hydration energy, energy released from water reactions
- Oral rehydration therapy, hydration as a health treatment