F-40

F-40, F.40 or F40 may refer to:
* EMD F40PH, a diesel locomotive
* Farman F.40, a 1915 French pusher biplane reconnaissance aircraf
* Ferrari F40, a 1987 Italian mid-engine sports car
* HMS Jervis Bay (F40), a 1940 British Royal Navy armed merchant cruiser
* HMS Sirius (F40), a 1964 British Royal Navy Leander-class frigate
* INS Talwar (F40), a 2000 Indian Navy Talwar class frigate

and also :
* The NATO code for JP-4 jet fuel
* Phobic anxiety disorders code