FN may refer to:
- fn key, a key found on some compact keyboards
- FN Herstal or Fabrique Nationale de Herstal, a Belgian arms factory
- FN (motorcycle), the motorcycles produced by FN Herstal
- Front National (France), a French political party
- Front National (French Resistance), a World War II French Resistance group
- Front National (Belgium), a Belgian political party
- Regional Air Lines' IATA airline designator
- Faking News, Indian news satire website
- Fibronectin, a glycoprotein involved in cell adhesion and growth