PEM or Pem may stand for:
People
- Pem Sluijter (1939 – 2007), Dutch poet
Science
- Photoelastic modulator
- Polyelectrolyte multilayer
- Positron emission mammography
- Proton exchange membrane, semipermeable
Engineering
- Power Entry Module
- PEM nut or self-clinching nut
Computing
- PCI Express Mini, a computer bus standard
- Privacy-Enhanced Mail
- .pem, a filename extension for an X.509 certificate
Medicine
- Polioencephalomalacia
- Protein-energy malnutrition
- Pediatric emergency medicine
- Post-exertional malaise
Other
- Peabody Essex Museum
- Padre Aldamiz International Airport, Madre de Dios, Peru, IATA code
- Pemberton railway station, England; National Rail station code
- Private electronic market