| JAFNA | Joint Air Force NASA Facility | - | Business and Finance |
| JAROS | Japan Resources Observation System Organization | - | Business and Finance |
| JAS | Journal Of The Atmospheric Sciences | - | Business and Finance |
| JASIN | Joint Air-Sea Interaction Experiment | - | Business and Finance |
| JASON | Group Of Physicists At Stanford That Study Various Projects And Are Funded By Government Defense Money | - | Business and Finance |
| JAWOP | Joint Automated Weather Observing Program | - | Business and Finance |
| JAWS | Joint Airport Weather Studies | - | Business and Finance |
| JCAE | Joint Committee On Atomic Energy | - | Business and Finance |
| JCL | Job Control Language | - | Business and Finance |
| JCP/ PO | Joint Climate Program/Projects Office | - | Business and Finance |
| JCS | Joint Chiefs Of Staff | - | Business and Finance |
| JEC | Joint-Evaluation Committee | - | Business and Finance |
| JEFNIC | Jeffco Network Infrastructure Completion Project | - | Business and Finance |
| JEM | Joint Environmental Monitoring | - | Business and Finance |
| JERS | Japan Earth Remote Sensing Satellite | - | Business and Finance |
| JERS-1 | Japanese Earth Resources Sensing Satellite 1 | - | Business and Finance |
| JES | Job Entry System | - | Business and Finance |
| JETDLAG | Part Of EUROTRAC | - | Business and Finance |
| JFSP | Joint Forecast System Project | - | Business and Finance |
| JGOFS | Joint Global Ocean Flux Study | - | Business and Finance |
| JGR | Journal Of Geophysical Research | - | Business and Finance |
| JHU | Johns Hopkins University | - | Business and Finance |
| JHWRP | Joint Hawaii Warm Rain Project | - | Business and Finance |
| JIC | Joint Implementation Committee | - | Business and Finance |
| JICA | Japan International Development Agency | - | Business and Finance |
| JICC | Japanese ICC | - | Business and Finance |
| JICP/PO | Now JOSS | - | Business and Finance |
| JILA | Joint Institute For Laboratory Astrophysics | - | Business and Finance |
| JMA | Japan Meteorological Agency | - | Business and Finance |
| JMG | Joint Meteorological Group | - | Business and Finance |
| JMOF | Joint Meteorological Observing Facility | - | Business and Finance |
| JMRNSC | Joint Meteorological Rocket Network Steering Committee | - | Business and Finance |
| JMSC | Joint Meteorological Satellite Communication | - | Business and Finance |
| JOC | Joint Organizing Committee | - | Business and Finance |
| JODC | Japan Ocean Data Center | - | Business and Finance |
| JOI | Joint Oceanographic Institutions | - | Business and Finance |
| JONSWAP | Joint North Sea Wave Project | - | Business and Finance |
| JOSS | Joint Office For Science Support | - | Business and Finance |
| JPL | Jet Propulsion Laboratory | - | Business and Finance |
| JPOP | Japanese Polar Orbiting Platform | - | Business and Finance |
| JPS | Joint Planning Staff | - | Business and Finance |
| JSC | Johnson Space Center | - | Business and Finance |
| JSC | Joint Scientific Committee | - | Business and Finance |
| JSPO | Joint Systems Program Office | - | Business and Finance |
| JTA | Job Table Area | - | Business and Finance |
| JVNC | John Von Neumann National Supercomputing Center | - | Business and Finance |
| JVNTSC | John Volpe National Transportation Systems Center | - | Business and Finance |
| JWG | Joint Working Group | - | Business and Finance |
