S17

S17 may refer to :
* , a safety phrase in chemistry
* S17 postcode for Sheffield areas of Dore, Totley and Bradway
* British NVC community S17, a swamps and tall-herb fens community in the British National Vegetation Classification system
* County Route S17 (California)
* Greek submarine Amfitriti (S-17) (1958-1967), a Gato class submarine
* HMS Ocelot (S17), a 1962 British Royal Navy Oberon-class diesel-electric submarine
* USS S-17 (SS-122), a 1921 S-class submarine of the United States Navy

; a shortening or designation for :
* a Zürich S-Bahn line