PACS is an acronym with several meanings:
- Cape Sarichef Airport (ICAO airport code), on Unimak Island of the Aleutian Islands, Alaska
- Pacte civil de solidarité, a form of civil union in France
- Palo Alto Chinese School, Palo Alto, California, USA
- Partial Anterior Circulation Stroke Syndrome, the symptoms of a type of an ischemic stroke
- Peace and conflict studies, an academic field that identifies and analyzes violent and nonviolent behaviors of social conflicts
- Photodetecting Array Camera and Spectrometer, an instrument of the Herschel Space Observatory
- Physics and Astronomy Classification Scheme, a scheme developed by the American Institute of Physics
- Picture Archiving and Communication System, a system used in medical imaging to store, retrieve, distribute, analyze, and digitally process medical images.
- Poorest Areas Civil Society Program (2001–2008), a defunct Indian social welfare program
- Primary airport control station, a survey marker established in the vicinity of an airport
- Prince Avenue Christian School, Oconee County, Georgia, USA
- Provisional Army of the Confederate States, the "volunteer" or wartime-expansion component of the Confederate States Army
PACs is the plural of PAC; for example:
- Political action committees, groups organized to elect or defeat political candidates
- Premature atrial contractions