BNF may refer to:
Science
- Backus–Naur form, a formal grammar notation in computer science
- Biological nitrogen fixation
- British National Formulary, a drug reference manual
- β-Naphthoflavone, an organic compound
Organisations
- British Nutrition Foundation, a charity
- Bibliothèque nationale de France (BnF), the French national library
Political parties
- Balawaristan National Front, Pakistan
- Belarusian National Front (Belarusian: Belaruski Narodny Front)
- BPF Party, break-away group from 1993 (Belarusian: Partyja BNF)
- Botswana National Front
Other uses
- Big Name Fan, a well-known fan