BLF may refer to:
- Bangladesh Liberation Front, also called Mujib Bahini
- Balochistan Liberation Front
- Beard Liberation Front
- Bellows Falls (Amtrak station); Amtrak station code BLF
- Billboard Liberation Front
- British Lung Foundation
- Brotherhood of Locomotive Firemen, forerunner of the Brotherhood of Locomotive Firemen and Enginemen
- Builders Labourers Federation in Australia
- Mercer County Airport (West Virginia); IATA airport code BLF