C45

C45 or C-45 may refer to:


 * Beech C-45 Expeditor, an American military transport aircraft
 * C4.5 algorithm, used to generate a decision tree
 * C45 road (Namibia)
 * Caldwell 45, a spiral galaxy
 * Cannabis Act introduced as Bill C-45 to the Parliament of Canada
 * EADS/Northrop Grumman KC-45, a cancelled air refueling aircraft for the US Air Force
 * Scotch Game, a chess opening
 * Underground Work (Women) Convention, 1935 of the International Labour Organization
 * Ursus C-45, a Polish tractor
 * C45, a variant of Claridge Hi-Tec/Goncz Pistol rifle
 * C45, a 45-minute audio Compact Cassette tape
 * C45 Scaphandre Autonome, vintage scuba equipment