S66

S66 may refer to:
 * S66 (Long Island bus)
 * S66 (New York City bus) serving Staten Island
 * Awabakal language
 * Daihatsu Hijet (S66), a Japanese kei truck
 * Explorer S-66, a failed American spacecraft
 * Savoia-Marchetti S.66, an Italian flying boat
 * S66, a postcode district for Rotherham, England
 * Siemens S66, a Siemens mobile phone