| O/B | OutBoard |
| O&A | Orbit and Attitude |
| O&M | Operations and Maintenance |
| O&S | Operations and Sustainment/Support |
| O&SHA | Operating and Support Hazard Analysis |
| OA | Operational Analysis/Availability |
| OAIS | Open Archival Information System |
| OAIT | Office Automation and Infrastructure Technology |
| OAR | Office of Atmospheric Research |
| OAS | Operational Algorithm Service |
| OASIS | Organization for the Advancement of Structured Information Standards |
| OASYS | Orbit/Attitude System |
| OATS | Orbit and Attitude Tracking System |
| OB | Optical Bench |
| OBC | On-Board Computer |
| OBMGR | Operations Baseline Manager |
| OBW | off bi-weekly |
| OC | Object Classes |
| OC | Operational Checkout |
| OCCB | Operations Configuration Control Board |
| OCCR | Operations Configuration Change Request |
| OCD | Operations Concept Document |
| OCE | Office of the Chief Engineer |
| OC/ECI | OC/Environmental Calibration Initialization |
| OCFO | Office of the Chief Financial Officer |
| OCFS | Oracle Cluster File System |
| OCI | Oracle Call Interface |
| OCI | Organizational Conflict of Interest |
| OCIO | Office of the Chief Information Officer (DOC) |
| OCKO | Office of Chief Knowledge Officer |
| OCONUS | Outside CONUS |
| OCP | Over Current Protection |
| OCS | Office of the Chief Scientist |
| OCWWS | Office of Climate, Water and Weather Services |
| OD | Ocean dynamics |
| OD | Orbit determination |
| ODA | Orbital debris assessment |
| ODBC | Open Data Base Connectivity |
| ODC | Other Direct Cost |
| ODDS | Oxidizer Depleting Detection System |
| ODE | Orbit Determination Element |
| ODF | Open Document Format |
| ODPA | Ocean Dynamics Product Algorithm |
| ODSF | Optical Depth Scaling Factor |
| ODT | Objective Dvorak Technique |
| OE | Operational Environment |
| OE | Optimal Estimation |
| OEM | Original Equipment Manufacturer |
| OFA | Output Filter Assembly |
| OFCM | Office of the Federal Coordinator for Meteorology |
| OFI | Other Functional Initiative |
| OGC | Office of General Council (DOC) |
| OGC | Other Government Cost |
| OGE | Operations Ground Equipment (GOES-I/P) |
| OGE | Oracle Grid Engine |
| OGSE | Optical Ground Support Equipment |
| OH | Optical Head |
| OHA | operations hazard analysis |
| OI | Optimum Interpolation |
| OID | Object Identifier |
| OISST | Optimal Interpolation Optimal Interpolation Sea Surface Temperature |
| OLI | Operational Land Imager |
| OLR | Outgoing Longwave Radiation (refers to the GOES-R product Upward Longwave Radiation: TOA) |
| OM | Observatory Manager |
| OMAO | Office of Marine and Aviation Operations |
| OMAS | Operational Metadata Aggregation Service |
| OMAT | Operational Mission Allowable Temperatures |
| OMB | Office of Management and Budget |
| OMI | Ozone Monitoring Instrument |
| OMPS | Ozone Mapping and Profiling Suite |
| OO | Object Oriented |
| OOD | Object Oriented Design |
| OORA | Object oriented Requirements Analysis |
| OPAL | Open Process Automation Library |
| OPAL | Orchestration and Provisioning Automation Library |
| OPC | Ocean Prediction Center |
| OPERA | On-demand PERformance Advisor |
| OPERM | Office of Program Evaluation and Risk Management |
| OPNET | Optimized Network Engineering Tools |
| OPO | Operations Project Office |
| OPS | Operations |
| OPSA | Optical Port Sunshield Assembly |
| OPSCON / OpsCon | Operations Concept |
| OPZ | Operations Zone |
| OR | Orbit Raising |
| ORA | Office of Research and Applications (NESDIS) |
| ORCA | Online Representations and Certifications Application |
| ORCA | Operations Readiness Checkout Activity |
| ORF | Orbit Reference Frame |
| ORIA | Office of Research Integrity and Assurance |
| ORM | Object-Relational Mapping |
| ORR | Operations Readiness Review |
| ORTT&C | Orbit Raising, Tracking, Telemetry and Command |
| OS | Operating System |
| OS | Optical Sensor |
| OSAAP | Office of System Architecture and Advanced Planning |
| OSB | Oracle Service Bus |
| OSC | On-orbit Storage Capability |
| OS/COMET | Harris’ Satellite Command and Control Tool Suite |
| OSCSB | OS/COMET Service Bus |
| OSD | Office of Systems Development (NESDIS) |
| OSDPD | Office of Satellite Data Processing and Distribution (NESDIS) |
| OSGS | Office of Satellite Ground Services/Support (NESDIS) |
| OSHA | Occupational Safety and Health Administration |
| OSHA | Operating and Support Hazard Analysis |
| OSI | Open Systems Interconnection |
| OSL | Open Source License |
| OSMA | Office of Safety and Mission Assurance |
| OSMA/SARD | OSMA/ Safety and Assurance Requirements Division (NASA) |
| OSO | Office of Satellite Operations (NESDIS) |
| OSP | Office of Strategic Planning |
| OSPF | Open Shortest Path First |
| OSPO | Occupational Safety Program Office |
| OSPO | Office of Satellite and Product Operations (NESDIS) |
| OSR | Optical Solar Reflectors |
| OSS | Open Source Software |
| OSSMA | Office of Systems Safety and Mission Assurance |
| OS&T | Office of Science & Technology, National Weather Service |
| OST | Over-the-Shoulder Training |
| OSTB | Offline Storage Transfer Buffer |
| OSTIA | Operational Sea Surface Current Temperature and Sea Ice Analysis |
| OSY | Office of Security |
| OTB | Optical Testbed |
| OTB | Optical Test Bench |
| OTB | Over Target Baseline |
| OTD | Optical Transient Detector |
| OTIM | One-dimensional Thermodynamic Ice Model |
| OTS | Off-The-Shelf |
| OTS | Over Target Schedule |
| OU | Organizational Units |
| OV | On-orbit verification |
| OV | Operator View |
| OVAL | Open Vulnerability Assessment Language |
| OVO | Open View Operations |
| OVP | Over Voltage Protection |