| Acronym | Meaning |
 | OGS | Quantity Gaging System |
 | OGV | Oxygen Gage Valve |
 | OH | Overhaul |
 | OH | Overhead |
 | OHA | Operational Hazard Analysis |
 | OHA | Orbital Height Adjustment Maneuver |
 | OHC | Onboard Hard Copier |
 | OHC | Optics Hand Controller |
 | OHF | Occupational Health Facility |
 | OHGVT | Orbiter Horizontal Ground Vibration Test |
 | OHMM | Ohmmeter |
 | OI | Operational Instrumentation |
 | OIA | Office Of International Affairs |
 | OIA | Orbiter Interface Adapter |
 | OIB | Orbiter Interface Box |
 | OIC | Orbiter (Orbital) Integrated Checkout |
 | OIL | Operations Integration Instruction |
 | OIR | Operations IntegrationReview |
 | OIS | Operational Intercommunication System |
 | OIS | Orbiter Instrumentation Systems |
 | OISR | Open Item Status Report |
 | OISSP | Office Of Interim Space Station Program |
 | OIT | Orbiter Integrated Test |
 | OIV | Oxidizer Isolation Valve |
 | OIVS | Orbiter Interface Verification Set |
 | OJT | On-the-Job Training |
 | OL | Open Loop |
 | OL | Operational Left DSC Or MDM |
 | OLDB | On-Line Data Bank |
 | OLDR | Quick Look Data Reference |
 | OLF | Orbiter Landing Facility (now SLF) |
 | OLIF | Orbiter Landing Instrumentation Facilities |
 | OLOW | Orbiter Lift-off Weight |
 | OLSA | Orbiter/LPS Signal Adapter |
 | OLSP | Orbiter Logistics Support Plan |
 | OM | Operational Mid DSC Or MDM |
 | OM | Optical Master |
 | OM | Orbital Maneuvering Engine |
 | OM | Orbiter Main Engine |
 | OM | Outer Marker (ILS) |
 | OM | RS Operations And Maintenance Requirements Specification |
 | OMA | Operations Maintenance Area |
 | OMA | Orbiter Maintenance Area |
 | OMB | Office Of Management And Budget |
 | OMBUU | Orbiter Midbody Umbilical Unit |
 | OMC | Orbiter Maintenance And Checkout |
 | OMCF | Operations And Maintenance Control File |
 | OMCF | Orbiter Maintenance And Checkout Facility |
 | OMD | Operations And Maintenance Documentation |
 | OMD | Orbiter Mating Device |