| Acronym | Meaning |
| OSS | Office of Strategic Services |
| OSS | Objective Supply System |
| OSS | Occupant Sensing System |
| OSS | Ocean Surveillance System |
| OSS | Office of Space Science |
| OSS | Office of Space Station (NASA) |
| OSS | Office of Space Systems |
| OSS | Office of Special Security |
| OSS | Office of Special Services |
| OSS | Office of Statistical Standards |
| OSS | Office of Systems Support |
| OSS | Office of the Secretary of State |
| OSS | Officer Safety and Survival Training Program (US FEMA) |
| OSS | Official Statistics System (New Zealand) |
| OSS | Old Submarine (US Navy) |
| OSS | On-Board Support Software |
| OSS | Online Schedule System |
| OSS | Online Subscription Service (various organizations) |
| OSS | Onsite Sewage System |
| OSS | Ontario Seniors Secretariat (Canada) |
| OSS | Operation Safer Streets (police task force) |
| OSS | Operation Spartan Shield (US Army) |
| OSS | Operation Support System |
| OSS | Operational Sequencing System (US Navy) |
| OSS | Operational Storage Site |
| OSS | Operational Support Services |
| OSS | Operational Support Summary |
| OSS | Operational Support System |
| OSS | Operational Support System (THREAT) |
| OSS | Operations Support Services |
| OSS | Operations Support Squadron |
| OSS | Optical Sight System |
| OSS | Optical Surveillance System |
| OSS | Optional State Supplementation |
| OSS | Overall System Sensitivity (radar) |
| OSS | Overhead Sign Structure (transportation; various locations) |