| Ocasio Consulting, LLC | Florida |
| OCC Hosting | Florida |
| Occam Design | |
| OccamzRazor | New York |
| Occasion | Illinois |
| Occhem Labs, LLC | |
| Occidental College | California |
| Occidental College Mathematics | California |
| Occupational Health Systems, Inc. | California |
| Occur | |
| Occuspace | |
| OCDesignsOnline | |
| Ocean 5 Strategies | |
| Ocean Azul Partners | Florida |
| Ocean Blue Digital | |
| Ocean Blue Technologie | Kentucky |
| Ocean Computers, Inc. | California |
| Ocean County College School of Science, Technology, Engineering and Math | New Jersey |
| Ocean Data Systems | |
| Ocean Park Technology | California |
| OCEAN Programs | Ohio |
| Ocean Propeller Fund | Massachusetts |
| Ocean Shark | |
| Ocean Software Solutions | Florida |
| Ocean Systems, Inc. | Florida |
| Ocean Tech Hub | |
| OCEAN User Group of Southern California | California |
| Ocean Wide | |
| Ocean Zero | |
| Oceaneering International, Inc. | |
| Oceanhouse Media, Inc. | California |
| OceanManager, Inc. | California |
| Oceanology International Americas | California |
| Oceans Ventures | New York |
| OceanSound Partners | |
| OceanSync Data Solutions, Inc. | |
| OceanTech | Minnesota |
| Oceanus World Link Services, Inc. | Connecticut |
| OceeNET Online | Tennessee |
| Ocelot Bio | California |
| OCG Creative | |
| OchsnerBrand.com | Texas |
| Ocient | Illinois |
| OCImagine | |
| Ocius Technologies | |
| Ockam | California |
| Ockers Company | Massachusetts |
| OCLAD Engineering | Texas |
| OCloud Solutions | |
| OCMS Bio, LLC | Pennsylvania |