C3I

C3I may refer to:
 * Command, Control, Communications and intelligence, a military abbreviation
 * Command, Control, Communications and Information, a British military abbreviation
 * The C3I Programme, an initiative of London's Metropolitan Police Service
 * Cambridge Centre for Ceramic Immobilisation, a UK-based nuclear waste disposal research body
 * Christian City Churches International, an Australia-based evangelical movement
 * C3i, a GMT Games magazine published by Rodger B. MacGowan
 * 3CI - Comradeship, Commitment, Courage and Integrity, a New Zealand military abbreviation

C3i, Campp 3 Innovation