S6

S6 or S-6 may refer to:

Routes

 * S6 (Berlin), a S-Bahn line
 * S6 (Milan suburban railway network)
 * S6 (Munich), a S-Bahn line in Munich
 * S6 (Rhine-Main S-Bahn)
 * S6 (Rhine-Ruhr S-Bahn), line
 * S6 (St. Gallen S-Bahn)
 * S6 (ZVV), a S-Bahn line in the cantons of Zürich and Aargau in Switzerland
 * County Route S6 (California)
 * Expressway S6 (Poland)
 * Essex, a county of England
 * S6 postcode, covering areas of north western Sheffield
 * a Hanover S-Bahn, line
 * a Rhein-Ruhr S-Bahn, line
 * a Rhine-Main S-Bahn, line
 * a Stuttgart S-Bahn, line
 * a Stadtbahn Karlsruhe, line
 * Tongmi line

Science

 * Ribosomal protein s6
 * S6: Keep under ... (inert gas to be specified by the manufacturer), a safety phrase in chemistry
 * hexasulfur, a cyclic sulfur allotrope
 * the symmetric group of degree six

Technology

 * Samsung Galaxy S6, a smartphone produced by Samsung
 * Samsung Galaxy Tab S6, an Android tablet
 * S6 NBC Respirator, the protective gas mask issued to the British armed forces from 1966 up until the introduction of the current-issue S10 in 1986
 * S6 truss, a part of the International Space Station

Vehicles

 * Audi S6, a car
 * ALCO S-6, and American diesel switching (shunting) locomotive
 * Prussian S 6, a 1906 steam locomotives class
 * Rans S-6 Coyote II, a light aircraft
 * Supermarine S.6 (1929), and Supermarine S.6B (1931), British racing seaplanes
 * USS S-6 (SS-111), a 1919 S-class submarine of the United States Navy
 * HMS Cachalot (S06), a 1957 British Porpoise-class submarine

Other uses

 * Staff (military), a communications officer within military units
 * Star Air (Denmark), IATA airline designator
 * S6 (classification), a paralympic swimming classification