| Opera CRO | |
| Opticnet | Bucharest |
| Optima Group | Bucharest |
| OptimizareSEOro | |
| Oracle Romania | Bucharest |
| Orange Fab România | Bucharest |
| Orange România | |
| Oranta IT Solutions | Cluj |
| Ordmark S.R.L. | Bucharest |
| ORESA Ventures | Bucharest |
| OTP Bank România | Bucharest |
| Outside Software, Inc. | Bucharest |
| Oveus S.R.L. | Bucharest |
| Oxygen IT | Bucharest |
| Oxygen XML Editor | Dolj |
| OZ Web Design | Brașov |
| P4B | |
| PadiCode S.R.L. | |
| Pagelocity | Dolj |
| Pago | Bucharest |
| Pandora | Bucharest |
| Panovision | Bucharest |
| Patria Bank S.A. | Bucharest |
| Patria Credit | |
| Paymo LLC | Bihor |
| PBWorks Web S.R.L. | Bucharest |
| PC House | Mureș |
| PC-coolers | Bucharest |
| PcAlba | Alba |
| Pcbit Electronics | |
| Pcmall | Bihor |
| PCZONE | Bucharest |
| Pentagon | Bucharest |
| Pentest Tools | |
| Pepas Cloud | |
| Peruvision | Timiș |
| Phobos Soft Co. S.R.L. | Bucharest |
| Phone Service Telecom | Bucharest |
| Pidgin Host S.R.L. | Bucharest |
| PinBud România | Bucharest |
| Pirostop Security | |
| PixelSolutions | |
| Pixobit | |
| PlanningWiz Ltd | Cluj |
| Playtech.ro | |
| Plin Tech Romania S.R.L. | |
| Plum Media | Bucharest |
| Pluri Consultants | |
| Plus Communication Consulting S.R.L. | |
| PlusPC | Bucharest |