| CIO | (Everybody I) See I Owe 
| Others |
| CIO | Career is Ongoing
| Others |
| CIO | Career Is Over
| Others |
| CIO | Cargo Integration Officer
| Others |
| CIO | Carrier Insertion Oscillator
| Others |
| CIO | Case Information Online
| Others |
| CIO | Center for Intercultural Organizing
| Others |
| CIO | Central Imagery Office
| Others |
| CIO | Central Informatics Organization
| Others |
| CIO | Central Input Output
| Others |
| CIO | Central Intelligence Officer
| Others |
| CIO | Centre d'Information et d'Orientation
| Others |
| CIO | Centre of Internal Operations
| Others |
| CIO | Check It Out
| Others |
| CIO | Cheif Information Officer
| Others |
| CIO | Chief Information Officers
| Others |
| CIO | Chief Information Optimist
| Others |
| CIO | Chief Internet Officer
| Others |
| CIO | Chief Investment Officer
| Others |
| CIO | Chill It Out
| Others |
| CIO | Church Information Office
| Others |
| CIO | Cisco Information Online
| Others |
| CIO | City One, Hong Kong
| Others |
| CIO | Clever Information Officer
| Others |
| CIO | Clinical Interventional Oncology
| Others |
| CIO | Collaborative Internet Observatory
| Others |
| CIO | Collective Input Output
| Others |
| CIO | College Informatics Olympiad
| Others |
| CIO | Command Intelligence Officer
| Others |
| CIO | Commision Internationale d'Optique
| Others |
| CIO | Committee of Industrial Organizations
| Others |
| CIO | Companion of the Imperial Order
| Others |
| CIO | Completely Insane Organization
| Others |
| CIO | Compliance Information Officer
| Others |
| CIO | Computer Integrated Office
| Others |
| CIO | Congress Industrial Organizations
| Others |
| CIO | Congress of Industrial Organizations
| Others |
| CIO | Coordinating Information Officer
| Others |
| CIO | Coordination, Implementation, and Operation
| Others |
| CIO | Corporate Information Office
| Others |
| CIO | Corporate Information Officer
| Others |
| CIO | Corporate Intelligence Officer
| Others |
| CIO | Corticosteroid-Induced Osteoporosis
| Others |
| CIO | Credit and Investments Ombudsman
| Others |
| CIO | Cry It Out
| Others |
| CIO | Crying It Out
| Others |
| CIO | Current Imagination Operations
| Others |
| CIO | Cut It Out
| Others |
| CIO | Cyprus Informatics Olympiad
| Others |