C51

C51 or C-51 may refer to:

Legislation

 * Anti-terrorism Act, 2015, introduced as Bill C-51 in the 41st Canadian Parliament, 2nd Session
 * Bill C-51 of the 39th Canadian Parliament, 2nd Session, a proposed amendment to the Food and Drugs Act

Vehicles

 * ARM General Juan N. Mendez, an Admirable-class minesweeper of the Mexican Navy
 * Caudron C.51, a French biplane floatplane
 * Douglas C-51, an American transport aircraft
 * JNR Class C51, a Japanese steam locomotive

Other uses

 * Caldwell 51, an irregular dwarf galaxy
 * Evans Gambit, a chess opening
 * GeForce 6100, a graphics processing unit