| 381 Design | |
| 39 Celcius | |
| 397 Digital | |
| 3A Systems, LLC | Washington |
| 3Advance | District of Columbia |
| 3AKIS, Inc. | New York |
| 3ALICA | |
| 3Angle Corporation | |
| 3Avenir | Tennessee |
| 3B Staffing | |
| 3Bears Designs | California |
| 3by400, Inc. | Georgia |
| 3C Network Consultants | Florida |
| 3C Software | Georgia |
| 3Circle Media | |
| 3Cloud | Illinois |
| 3clx.com | Florida |
| 3Core Software, Inc. | Texas |
| 3Core Systems, Inc. | Texas |
| 3CPM Company, Inc. | Maryland |
| 3CX Academy | Georgia |
| 3D Biotek, LLC | New Jersey |
| 3D Cloud by Marxent | Florida |
| 3D Control Systems Ltd | California |
| 3D Digital | |
| 3D Enterprises, Inc. | Ohio |
| 3D Extreme, Inc. | Illinois |
| 3D Group | California |
| 3D Health Solutions | |
| 3D Inspection System | Florida |
| 3D Maritime, Inc. | |
| 3D Math Primer for Graphics and Game Development | |
| 3D Media Now | |
| 3D Net Productions | Florida |
| 3D Perception | Florida |
| 3D Source | Illinois |
| 3D Systems, Inc. | South Carolina |
| 3D Tek, Inc. | Florida |
| 3D-Rex & AniRex Studios, Inc. | |
| 3D-Rex Studios | Illinois |
| 3Data | Texas |
| 3Daughters | Massachusetts |
| 3DBioCAD | Washington |
| 3DEO, Inc. | Massachusetts |
| 3Derm | Massachusetts |
| 3DEX, Inc. | |
| 3DFortify, Inc. | Massachusetts |
| 3Di Systems | |
| 3DiVi, Inc. | California |
| 3DLabs Inc. Ltd | California |