| Acronym | Meaning |
| IOC | In-Orbit Construction (NASA) |
| IOC | Indirect Operating Cost |
| IOC | Industrial Operations Command |
| IOC | Infantry Officers' Course (USMC) |
| IOC | Initial Operational Capability |
| IOC | Initial Operational Clearance |
| IOC | Innocent Owner/Operator Certificate |
| IOC | Innovation Ontario Corporation (Government of Ontario Corporation) |
| IOC | Input Output Cabinet |
| IOC | Inspector on Call |
| IOC | Integrated Operations Center (various organizations) |
| IOC | Inter-Office Channel |
| IOC | Interagency Operations Center |
| IOC | Intercept Operations Center |
| IOC | Intergovernmental Oceanographic Commission (UNESCO) |