S38 may refer to:
*
BMW S38, an automobile engine
*
S38: In case of insufficient ventilation wear suitable respiratory equipment, a safety phrase
*
Short S.38, a British biplane
*
Sikorsky S-38, a 1928 American amphibious sesquiplane
*
Sulfur-38, an isotope of sulfur
* , a submarine of the United States Navy
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