| Acronym | Meaning |
| SMI | Safety Management Institute (various organizations) |
| SMI | Saturday Morning Inspection |
| SMI | School Meals Initiative for Healthy Children (USDA) |
| SMI | Security Management Information |
| SMI | Security Management Infrastructure |
| SMI | Senior Marine Instructor (USMC JROTC) |
| SMI | Senior Military Instructor (Army ROTC) |
| SMI | Sergeant Major Instructor |
| SMI | Ship Manpower Information |
| SMI | Ship Modification Instruction |
| SMI | Site of Metropolitan Importance (UK) |
| SMI | Smart Metering Infrastructure (Australia) |
| SMI | Smart Metering Initiative (Canada) |
| SMI | Soldier/Machine Interface |
| SMI | Southern Military Institute |
| SMI | State Median Income |
| SMI | Structured Management Information |
| SMI | Supplementary Medical Insurance |
| SMI | Supply Management Inspection |
| SMI | Surface Minimum d'Installation (French: Minimum Installation Area; farming) |