S53

S53 may refer to:
 * S53 (New York City bus), serving Staten Island
 * Dhurga language, an Australian Aboriginal language
 * S53: Avoid exposure - obtain special instructions before use, a safety phrase
 * Shorland S53, a British armoured car
 * Sikorsky S-53, an American helicopter
 * Tsonga language, a Bantu language
 * Saviem S53, a Saviem bus model
 * Toyota S53, a Toyota S transmission
 * ZIS-S-53, an Anti air and Anti-tank gun