| Omnitronix | Sofia |
| ONDO | Sofia |
| Onebit Software | Sofia |
| Ontotext | Sofia |
| Open Source University | Sofia |
| Opencode | Sofia |
| Opencode Systems Ltd | Sofia |
| OpenFest | Sofia |
| Optimall Solutions | Sofia |
| Optimystica | |
| ORAK Engineering | Plovdiv |
| Orange Sputnik | |
| OrangeTrail Ltd | Sofia |
| Orgtechnica Ltd | Silistra |
| ORM.BG | Sofia |
| OutsourceBG Services Ltd | Sofia |
| Ovalpixels, LLC | Sofia |
| OvertAim Coworking Space | Sofia |
| Oбединена българска банка | Sofia |
| Pagescreen | Sofia |
| Palmo Ltd | Sofia |
| Para | Sofia |
| Paraflow Communications Ltd | Sofia |
| Parallel Bulgaria Ltd | |
| Paynetics AD | Sofia |
| Paysera Bulgaria | Sofia |
| PC Mania | Sofia |
| PCLife Ltd | Sofia |
| pcstore.bg | Sofia |
| Pensoft Publishers | Sofia |
| People Solutions Factory | Sofia |
| Perspective Web | Sofia |
| PetrovSoft Ltd | Sofia |
| Phoenix Capital Holding plc | Sofia |
| Phos | Sofia |
| PHP Jabbers | Varna |
| Phyre | Sofia |
| Pixel House Studio | Sofia |
| Pixelmind | Sofia |
| Plasico IT Superstore | Sofia |
| PlayTime.BG | Sofia |
| PlazMax Computers | Sofia |
| Plesio | Sofia |
| Plovidv University | Plovdiv |
| Plus Minus Ltd | Sofia |
| Pollenity | Sofia |
| PolyComp | Sofia |
| Polymedia Ltd | Sofia |
| PowerHost.bg | Sofia |
| PowerNet | Sofia |