S61

S61 may refer to:

Naval vessels

 * HMAS Orion (S 61), of the Royal Australian Navy
 * INS Sindhukirti (S61), of the Indian Navy
 * SPANISH SUBMARINE Delfín

Rail and transit

 * S61 (Long Island bus)
 * S61 (New York City bus) serving Staten Island
 * S61, a line of the Styria S-Bahn

Other uses

 * Blériot-SPAD S.61, a French fighter aircraft
 * Chopi language
 * County Route S61 (Bergen County, New Jersey)
 * Expressway S61 (Poland)
 * S61: Avoid release to the environment. Refer to special instructions/safety data sheet, a safety phrase
 * Sikorsky S-61, an American helicopter
 * S61, a postcode district in Rotherham, England