| ICSO | Imperial College Symphony Orchestra 
| Others |
| ICSO | Imperial County Sheriff's Office
| Others |
| ICSO | Indigenous Cambodian Support Organization
| Others |
| ICSO | Indigenous Community Support Organisation
| Others |
| ICSO | Ingham County Sheriff's Office
| Others |
| ICSO | integrated Civil Society Organizations
| Others |
| ICSO | Internal Control Sarbanes-Oxley
| Others |
| ICSO | International Company Secretaries Olympiad
| Others |
| ICSO | International Conference on Space Optics
| Others |
| ICSO | International Container Security Organization
| Others |
| ICSO | Internet Computing Systems Optimization
| Others |