| JAGIS | Journalism and GIS Interest Group |
| JAMP | Joint Automated Mapping Project |
| JATOP | Army Topographic Service (Indonesia) |
| JCCDS | Joint Committee on Cartographic Data Standardization (U.S.) |
| JCP | Joint Committee on Printing (U.S. Congress) |
| JEC | John E. Chance & Associates |
| JECA | John E. Chance & Associates |
| JERS | Japanese Earth Resources Satellite |
| JFIF | JPEG File Interchange Format |
| J.H. | Jagerhaus = hunting lodge |
| JICA | Japan International Cooperation Agency = Kokusai Kyoryoku Jigyodan |
| JIGI | Java Interface for Geospatial Information |
| JISC | Joint Information Systems Committee |
| J&K | Jammu and Kashmir |
| JMC | Japan Map Center |
| JMPC | Joint Mapping and Photography Committee (U.S.) |
| JMT | Johnson, Mirmiran and Thompson (Firm) |
| JMTK | Joint Mapping Tool Kit |
| JNC | Jet Navigation Chart |
| JNGC | Jordan National Geographic Centre |
| JOG | Joint operations graphic |
| JOG-A | Joint operations graphic--air |
| JOG-G | Joint operations graphic--ground |
| JOG-R | Joint operations graphic--radar |
| JOIDES | Joint Oceanographic Institutions' Deep Earth Sampling |
| JOMAR | Joint Office for Mapping and Research (USGS-NOAA) |
| JPEG | Joint Photographic Experts Group |
| .JPG | Joint Photographic Experts Group format |
| JPL | Jet Propulsion Laboratory (U.S.) |
| JPS | Javad Positioning Systems, Inc. |
| Jr HS | Junior high school |
| JRI | Jordregisterinstituttet (Norway) |
| JSC | Johnson Space Center |
| JSD | Jamaica Survey Dept. |
| JTIDS | Joint Tactical Information Distribution System |
| JTU | Jabatan Tanah dan Ukur |
| JWPCF | Journal of the Water Pollution Control Federation |
| JWS | James W. Sewall Company, Inc. |