Hydrophobia may refer to:
- rabies, especially a set of symptoms of the later stages of an infection, in which the victim has difficulty swallowing, shows panic when presented with liquids to drink, and cannot quench his or her thirst.
- Aquaphobia, a morbid fear of water, or of swimming. It usually occurs in mild cases involving fear of deep water, and not as a general fear of the substance water.
- Hydrophobe, a term used in chemistry to describe chemical "aversions" of a molecule or part of a molecule.
- Hydrophobia (game), video game.