C14, C.XIV or C-14 may refer to:

• Autovía C-14, a highway in Catalonia in Spain
• Fokker C.XIV, a 1937 Dutch reconnaissance seaplane
• HMS C14, a 1908 British C-class submarine
• LSWR C14 class, a London and South Western Railway locomotive class
• LNER Class C14, a class of British steam locomotives
• Ramal C-14, the Argentinian track of the Salta–Antofagasta railway
• Sauber C14, a 1995 racing car
• C14 or S14 (Ukrainian group), a radical nationalist group in Ukraine
• The 14th century
• C 14-class missile boat, a light missile boat of catamaran design
• Carbon-14, a radioactive isotope of carbon
  • C-14 dating, a method for dating events
• IEC 60320 C14, a polarised, three pole socket electrical connector
• Boeing YC-14, an American experimental transport aircraft of the 1970s
• Malignant neoplasm of other and ill-defined sites in the lip, oral cavity and pharynx ICD-10 code
• C14 Timberwolf, a Canadian .338 Lapua sniper rifle
• Caldwell 14, the Double Cluster in the constellation Perseus
• French Defence, an Encyclopedia of Chess Openings code
• Concours 14 or Kawasaki 1400GTR, a 1,352cc motorcycle
• Bill C-14, a bill legalizing euthanasia in Canada