C42 or C-42 may refer to:
Vehicles Alfa Romeo C42, a Swiss Formula One car Douglas C-42, an American military transport aircraft Ikarus C42, a German microlight aircraft Neiva Regente C-42, a Brazilian military transport aircraft
Other uses C42 (TV channel), a former New Zealand television channel C42 road (Namibia) Caldwell 42, a globular cluster City 42, formerly C42, a television channel in Pakistan Petrov's Defence, a chess opening