S6

S6 or S-6 can mean:

; beginning with S6 :
* S6 (Berlin), a S-Bahn line
* , a safety phrase in chemistry
* S6 (military), a communications officer within military units
* S6 (Munich), a S-Bahn line in Munich
* S6 NBC Respirator, the protective gas mask issued to the British armed forces from the 1966 up until the introduction of the current-issue S10 in 1986
* S6 postcode, covering areas of north western Sheffield
* S6 (Rhine-Ruhr S-Bahn) line
* S6 truss, a part of the International Space Station

; containing S6 :
* Audi S6, a car
* British NVC community S6, a swamps and tall-herb fens community in the British National Vegetation Classification system
* Coolpix S6, a 6 Megapixels Nikon Coolpix series digital camera
* County Route S6 (California)
* Prussian S 6, a 1906 steam locomotives class
* Ribosomal protein s6
* Siemens S6, a Siemens mobile phone
* Star Air (Denmark), IATA airline designator
* Supermarine S.6 and Supermarine S.6B, two 1929 and 1931 racing seaplanes
* USS S-6 (SS-111), a 1919 S-class submarine of the United States Navy
* Yamaha S6, a hand-made Yamaha grand piano model

; a shortening or designation for :
* Essex, a county of England
* a Hanover S-Bahn line
* a Rhein-Ruhr S-Bahn line
* a Rhine-Main S-Bahn line
* a Stuttgart S-Bahn line
* a Zürich S-Bahn line
* a Stadtbahn Karlsruhe line

S₆ may refer to :
* hexasulfur, a cyclic sulfur allotrope

S06 may refer to :
* HMS Cachalot (S06), a 1957 British Porpoise-class submarine