C39 or C-39 may refer to:

Vehicles Aircraft Caudron C.39, a French passenger biplane Cessna C-39, an American civil utility aircraft Douglas C-39, an American military transport aircraft

Ships , a County-class cruiser of the Royal Navy

Surface vehicles Alfa Romeo Racing C39, an Italian Formula One car GE C39-8, a diesel electric locomotive Marshall C39, a British bus

Other uses C39 road (Namibia) Caldwell 39, a planetary nebula King's Gambit, a chess opening