| Oakland University School of Engineering and Computer Science | Michigan |
| Oakley Studio, LLC | New Mexico |
| OakNorth | |
| Oakpointe Consulting, LLC | Texas |
| Oakrum Pharma, LLC | |
| Oakstand Community Website Development | Oregon |
| Oakton College | Illinois |
| Oaktree Capital Management, L.P. | |
| Oakwood | Missouri |
| Oakwood Labs | Ohio |
| Oakwood Software Insurance Solutions, LLC | Texas |
| Oakwood University | Alabama |
| Oamii | |
| OANDA Corporation | |
| oApps Infotech | |
| oAppsNET Group | Colorado |
| OAREX Capital Markets, Inc. | |
| Oasis Biz Solutions | |
| Oasis Creative | |
| Oasis Diagnostics Corporation | Washington |
| Oasis Digital Solutions, Inc. | Missouri |
| Oasis Grafx | Maryland |
| Oasis Interactive, LLC | Idaho |
| Oasis Labs, Inc. | |
| Oasis LMS | Illinois |
| Oasis Online, Inc. | Nevada |
| OASIS Open | |
| Oasis Security | |
| Oasis Solutions | Kentucky |
| Oasis Systems, Inc. | Massachusetts |
| Oasis Technologies, Inc. | Oklahoma |
| Oasis Technology, Inc. | California |
| OASYS, Inc. | Alabama |
| Oatfi | |
| Obatala Sciences | Louisiana |
| OBCIDO, Inc. | |
| OBD Diagnostics, Inc. | California |
| Obelisk Enterprises | |
| Obello | |
| Oberlin College and Conservatory | Ohio |
| Oberlin College Computer Science | Ohio |
| Oberlin College Mathematics | Ohio |
| OBI Creative | |
| OBiO Tech, Inc. | |
| Object | |
| Object 9 | |
| Object Computing, Inc. | Missouri |
| Object Discovery Corporation | California |
| Object Edge | California |
| Object Knowledge, Inc. | Florida |