CAH can stand for:
- Congenital adrenal hyperplasia
- Calcium Aluminate Hydrate, an important phase in cement chemistry
- Community of All Hallows, an Anglican religious community for women
- Crime against humanity
- Cards Against Humanity, a party game.
- Capital Airports Holding Company, Airport holdings company in the People's Republic of China
- The ICAO airline designator for Charlan Air Charter, South Africa
- Cambridge Ancient History a bibliographic abbreviation for the work edited by Cambridge University Press
- Calvin and Hobbes, a newspaper comic strip from 1985 to 1995
- Cyanide and Happiness, a daily webcomic
- CAH is a mnemonic used to teach trigonometry, showing that cosine is the ratio of adjacent over hypotenuse.
- Beijing Capital International Airport