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
• 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