FAU or Fau may refer to:
- FAU (gene), part of the human genome
- Forced Air Unit, a type of heating system
- Le Fau, a commune in Cantal, France
- Fau (river), a river in Haute-Saône department, eastern France
- Florida Atlantic University, a university in Boca Raton, Florida, United States
- Friends' Ambulance Unit, an ambulance service founded by the British Religious Society of Friends
- Facultad de Arquitectura y Urbanismo, part of the University of Chile
- Federación Anarquista Uruguaya or Uruguayan Anarchist Federation
- Freie ArbeiterInnen-Union or Free Workers' Union, an anarcho-syndicalist labor union in Germany
- Friedrich-Alexander-Universität Erlangen-Nürnberg, the University of Erlangen-Nuremberg in Bavaria, Germany
- Fuerza Aérea Uruguaya or Uruguayan Air Force