| O AND A | Orbit And Altitude | - | Business and Finance |
| O AND E | Operations And Equipment | - | Business and Finance |
| O AND M | Operations And Maintenance | - | Business and Finance |
| O-LAPS | LAPS Ported To The University Of Oklahoma To Support VORTEX | - | Business and Finance |
| O-O | Object-oriented | - | Business and Finance |
| O/I | Optimal Interpolation | - | Business and Finance |
| OA | Office Automation | - | Business and Finance |
| OAO | Office Of Aircraft Operations | - | Business and Finance |
| OAR | Office Of Aerospace Research | - | Business and Finance |
| OAR | Oceanic And Atmospheric Research | - | Business and Finance |
| OAR | Office Of Atmospheric Research | - | Business and Finance |
| OAS | Organization Of American States | - | Business and Finance |
| OASC | Office Of Advanced Scientific Computing | - | Business and Finance |
| OASIS | Oceanic & Atmospheric Scientific Information System | - | Business and Finance |
| OASM | Operational Analysis Support Model | - | Business and Finance |
| OB | Optical Bench | - | Business and Finance |
| OBAC | Office Of Budget And Control | - | Business and Finance |
| OBC | Onboard Computer | - | Business and Finance |
| OBP | Onboard Processor | - | Business and Finance |
| OBS | Organizational Breakdown Structure | - | Business and Finance |
| OC | Operational Capability | - | Business and Finance |
| OCC | Operations Control Center | - | Business and Finance |
| OCE | Division Of Oceanic Sciences | - | Business and Finance |
| OCG | Ocean Catalog Group | - | Business and Finance |
| OCI | Ocean Color Imager | - | Business and Finance |
| OCM | Ocean Circulation Model | - | Business and Finance |
| OCME | Oceanographic Community Modeling Effort | - | Business and Finance |
| OCR | Optical Character Reader | - | Business and Finance |
| OCTA | Oxidizing Capacity Of The Troposphere Atmosphere | - | Business and Finance |
| OCTS | Ocean Color And Temperature Scanner | - | Business and Finance |
| OD | Outside Diameter | - | Business and Finance |
| ODE | Ordinary Differential Equation | - | Business and Finance |
| ODGA | Office Of Development And Government Affairs | - | Business and Finance |
| ODP | Ocean Drilling Program | - | Business and Finance |
| ODP | Ozone Depletion Potential | - | Business and Finance |
| ODP | Onboard Data Processor | - | Business and Finance |
| ODR | Onboard Data Router | - | Business and Finance |
| ODW | Omega Dropwindsonde | - | Business and Finance |
| OEA | Office Of External Affairs | - | Business and Finance |
| OECD | Organization For Economic Cooperation And Development | - | Business and Finance |
| OFAP | Observing Facilities Advisory Panel | - | Business and Finance |
| OFCM | Office Of The Federal Coordinator For Meteorology | - | Business and Finance |
| OFDA | Office Of Foreign Disaster Assistance | - | Business and Finance |
| OFPS | Office Of Field Project Support | - | Business and Finance |
| OFS | Office Of Field Project Support | - | Business and Finance |
| OGA | Office Of Government Affairs | - | Business and Finance |
| OGCM | Ocean General Circulation Model | - | Business and Finance |
| OGO | Orbiting Geophysical Observatory | - | Business and Finance |
| OGP | Office Of Global Programs | - | Business and Finance |
| OI | Optimal Interpolation | - | Business and Finance |
| OIES | Office For Interdisciplinary Earth Studies | - | Business and Finance |
| OIR | Office Of Industry Relations | - | Business and Finance |
| OIRTD | Office Of Industrial Relations And Technology Development | - | Business and Finance |
| OLE | Object Linking And Embedding | - | Business and Finance |
| OLR | Outgoing Longwave Radiation | - | Business and Finance |
| OM | Office Of Meteorology | - | Business and Finance |
| OMB | Office Of Management And Budget | - | Business and Finance |
| OMDR | Optical Memory Disk Recorder | - | Business and Finance |
| OMEGA | Operational And Prediction Multi-scale Environmental Model With Grid Adaptivity | - | Business and Finance |
| OMNET | N/A | - | Business and Finance |
| OMO | Office Of Meteorological Observations | - | Business and Finance |
| OMO | Orbiting Meteorological Observatory | - | Business and Finance |
| OMR | Optical Mark Reader | - | Business and Finance |
| OMTF | Optical Modulation Transfer Function | - | Business and Finance |
| ONERA | Office National D'Etudes Et De Recherches Aerospatiales | - | Business and Finance |
| ONERA | Office National D'Etudes Et De Recherches Aerospatiales | - | Business and Finance |
| ONR | Office Of Naval Research | - | Business and Finance |
| ONR/BO | Office Of Naval Research/Branch Office | - | Business and Finance |
| OO | Object Oriented | - | Business and Finance |
| OPAL | Opacity Project At Livermore | - | Business and Finance |
| OPC | Optical Propagation Conference | - | Business and Finance |
| OPENDAP | Open-source Project For A Network Data Access Protocol | - | Business and Finance |
| OPLE | OMEGA Position And Location Experiment | - | Business and Finance |
| OPLE | Omega Position Location Equipment | - | Business and Finance |
| OPP | Office Of Polar Programs | - | Business and Finance |
| OPPE | Office Of Policy | - | Business and Finance |
| OPS | Onboard Payload Support | - | Business and Finance |
| OPTRAN | Optical Test Transmittance Model | - | Business and Finance |
| OR | Operational Research | - | Business and Finance |
| ORB | Object Request Broker | - | Business and Finance |
| ORCP | Ocean Ridge Crest Processes | - | Business and Finance |
| ORD | Office Of Research And Development | - | Business and Finance |
| ORNL | Oak Ridge National Laboratory | - | Business and Finance |
| ORR | Operations Readiness Review | - | Business and Finance |
| ORSTOM | Institut Francais Pour Le Developpment En Corporation | - | Business and Finance |
| ORU | Orbital Replacement Unit | - | Business and Finance |
| OS | Oceanography Section | - | Business and Finance |
| OS/2 | A Multitasking Operating System Developed By IBM For Its PC-class Computers | - | Business and Finance |
| OSA | Optical Society Of America | - | Business and Finance |
| OSCAR | Oxidant-Scavenging Characteristics Of April Rains | - | Business and Finance |
| OSD | Office Of Systems Development | - | Business and Finance |
| OSDPD | Office Of Space Data Processing And Distribution | - | Business and Finance |
| OSF | Operational Support Facility | - | Business and Finance |
| OSI | Open Systems Interconnection | - | Business and Finance |
| OSIS | Office Of Scientific Information Service | - | Business and Finance |
| OSL | Orbiting Solar Laboratory | - | Business and Finance |
| OSO | Orbiting Solar Observatory | - | Business and Finance |
| OSO | Office Of Systems Operations | - | Business and Finance |
| OSO | Office Of Space Operations | - | Business and Finance |
| OSPF | Open Shortest Path First | - | Business and Finance |
