C13 or C-13 may be:
* French Defence, Encyclopaedia of Chess Openings code
* C13 White Lead (Painting) Convention, 1921
* C13 grenade, the Canadian Forces designation for a M67 grenade
* Autovia C-13, a highway in Catalonia in Spain
* Caterpillar C13 Engine, an engine by Caterpillar Inc.
* , a 1906 British C-class submarine
* IEC 60320 C13, a polarised, three pole plug used in electric power cables
* LNER Class C13, a 4-4-2T steam locomotive of 1907, built for suburban passenger services around London
* OTO Melara C13
* Sauber C13, a 1994 racing car
* Caldwell 13 (NGC 457, the Owl Cluster or ET Cluster), an open star cluster in the constellation Cassiopeia
* The 13th century
* in music, a chord with the structure 1 - 3 - 5 - b7 - 9 - 13
* Carbon-13, a natural stable isotope of carbon
* Head and neck cancer, Malignant neoplasm of hypopharynx ICD-10 code
* IEC 60320#C13/C14 coupler, C13/C14 Coupler, a class of cable connector used by most desktop computers
{{Letter-Number Combination Disambiguation
