F40

F40, F.40 or F-40 may refer to:

In transportation 

• EMD F40PH, a diesel locomotive
• Farman F.40, a 1915 French pusher biplane reconnaissance aircraft
• Ferrari F40, a 1987 Italian mid-engine sports car
• GM F40 transmission, a car gearbox

In military 

• 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
• HMS Roberts (F40)

and also :

• the NATO code for the JP-4 jet fuel
• the ICD-10 code for phobic anxiety disorders