3C

3C may refer to:

In astronomy:
 * 3C, the Third Cambridge Catalogue of Radio Sources, an astronomical reference series

In business: In computing:
 * Long March 3C, a 2008 Chinese orbital rocket
 * 3C Records, a record label
 * 3C (radio), a defunct digital radio station
 * Team 3C Casalinghi Jet Androni Giocattoli, a defunct Italian professional cycling team
 * 3C, the IATA code for defunct American airline RegionsAir
 * Three-cent piece
 * 3C (trade association) is an American trade association.
 * Three Cs (Compulsory, Capacity, and Conflict), three categories of CPU cache misses
 * 3C, or Computer Control Company, Inc., a pioneering minicomputer company (1953–1966)
 * Agile model: 3C (Card, Conversation, Confirmation)
 * 3C, an abbreviation often used in Taiwan for "computer, communication, and consumer electronics"

In genetics:
 * Alpha-tubulin 3C, a human gene
 * 3C, or Chromosome conformation capture, a technique used in molecular biology

Substituted amphetamines (2C family analogues):
 * 3C-G (Ganesha) with homologues
 * 3C-BZ
 * 3C-P
 * 3C-E

In places:
 * Stalag III-C, a German Army World War II POW camp for Allied soldiers near Alt-Drewitz