SLF may refer to:
- Seattle Liberation Front, anti-Vietnam War organization
- Shuttle Landing Facility, for the Space Shuttle
- Social Liberal Forum, UK
- Spotted lanternfly, an insect native to parts of China, India, and Vietnam, and recently invading parts of the eastern US
- Stephen Lewis Foundation
- Stiff Little Fingers, Northern Irish punk band
- Subscriber Location Function in IP Multimedia Subsystem
- Sun Life Financial, Canada
- Super low frequency electromagnetic waves
- Superior longitudinal fasciculus, an association fiber tract in the brain
- UD SLF, a bus
- Self loading freight, passengers
- Student loan forgiveness.