| Nubessom | |
| Nubesson Consulting | Prague |
| O2 Czech Republic, a.s. | |
| Oak's Lab | |
| Oaza-net, spol. s r.o. | |
| OBDTester.com | Prague |
| Octopod Systems, s.r.o. | |
| Oddin.gg | |
| Odyzeo, spol. s r.o. | |
| Office for Personal Data Protection | Prague |
| officerentinfo.cz | |
| Ogmio media, s.r.o. | Prague |
| OK Data, s.r.o. | |
| OKsystem | Prague |
| Oncomed Manufacturing, a.s. | |
| ONEsolution, s.r.o. | South Moravian |
| Onlio, a.s. | Prague |
| OPC Labs | Prague |
| Opero | |
| Optifor, s.r.o. | Prague |
| Optima Recruitment Europe, s.r.o. | |
| Optimalizace a SEO | Prague |
| Optimify, s.r.o. | |
| OptimSys, s.r.o. | South Moravian |
| ORBIT, s.r.o. | |
| Organizační kancelář Znojmo, spol. s.r.o. | |
| Orionet | |
| ORLEN Unipetrol RPA, s.r.o. | |
| Orlovanet.cz | |
| Oscar Senior, s.r.o. | |
| Ostravská univerzita | |
| P.V.A. systems, s r.o. | |
| P3 Logistics Parks, s.r.o. | |
| PalmApp | |
| PAMA, spol. s r.o. | Zlín |
| Panaxeo, s.r.o. | |
| Panevropská univerzita | |
| Pantek (CS), s.r.o. | Hradec Králové |
| Paralelní Polis | |
| PartnerCIS, s.r.o. | Zlín |
| Passengera | |
| Passion Communications | |
| PBS Group, a.s. | |
| PC - Servis Kozák | Central Bohemian |
| PC HELP, a.s. | Vysočina |
| pc-ambulance | Prague |
| PC-Progress s.r.o. | Prague |
| PCKURZY.cz | Prague |
| PCV Computers, s.r.o. | |
| PCWorld.cz | Prague |