| CIU | California International University 
| Others |
| CIU | Cardiac Investigation Unit
| Others |
| CIU | Categorical Industrial User
| Others |
| CIU | Cell Interface Unit
| Others |
| CIU | Center for International Understanding
| Others |
| CIU | Central Intelligence Unit
| Others |
| CIU | Central Intermediate Unit
| Others |
| CIU | Champion In U
| Others |
| CIU | Chippewa County International Airport, Sault Ste Marie, Michigan USA
| Others |
| CIU | Christ In Us
| Others |
| CIU | Chronic Idiopathic Urticaria
| Others |
| CIU | Clean It Up
| Others |
| CIU | Clinical Investigation Unit
| Others |
| CIU | Clinical Investigations Unit
| Others |
| CIU | Clone Intelligence Unit
| Others |
| CIU | Club and Institute Union
| Others |
| CIU | Collision Investigation Unit
| Others |
| CIU | Columbia International University
| Others |
| CIU | Commercial Insurance Underwriters
| Others |
| CIU | Committee for an Inclusive University
| Others |
| CIU | Common Interchange Unit
| Others |
| CIU | Communication Interface Unit
| Others |
| CIU | Communication Interface Unite
| Others |
| CIU | Communications Interface Unit
| Others |
| CIU | Community Intelligence Unit
| Others |
| CIU | Computer Interface Unit
| Others |
| CIU | Confederation of Independent Unions
| Others |
| CIU | Confederation of Independent Unions in the Public Sector
| Others |
| CIU | Confederazione Italiana Unionquadri
| Others |
| CIU | Consolidated Isotropically, sheared undrained
| Others |
| CIU | Control Interface Unit
| Others |
| CIU | Controller Interface Unit
| Others |
| CIU | Conviction Integrity Unit
| Others |
| CIU | Criminal Information Unit
| Others |
| CIU | Criminal Interdiction Unit
| Others |
| CIU | Criminal Investigation Unit
| Others |
| CIU | Criminal Investigations Unit
| Others |
| CIU | Criminal Investigative Unit
| Others |
| CIU | Criminals In Uniform
| Others |
| CIU | Critical Incident Unit
| Others |
| CIU | Culture Identity Unitpacks
| Others |
| CIU | Custom Installer Ultimate
| Others |
| CIU | Customer Interface Unit
| Others |
| CIU | Customs and Immigration Union
| Others |
| CIU | Customs Investigation Unit
| Others |