Hydrophobia may refer to one of the following.
- Hydrophobia, a set of symptoms of the later stages of a rabies infection, in which the victim has difficulty swallowing, shows panic when presented with liquids to drink, and cannot quench his or her thirst. "Hydrophobia" is also an old name for rabies itself.
- Hydrophobia, a phobia towards water, i.e., 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.
- Hydrophobia, a physical property of a molecule that is repelled by water.