| Open Seed S.r.l. | |
| Open1 S.r.l. | Ferrara |
| Openkey S.r.l. | Ascoli Piceno |
| OpenMall S.r.l. | |
| OpenVOIP | Rome |
| Opstart S.r.l. | |
| Optea S.r.l. | Bologna |
| Optima S.r.l. | Bologna |
| Opto Engineering S.r.l. | Mantua |
| Opyn | Milan |
| Oracle Italy | Milan |
| Orange Drop Design | Latina |
| Orga System | Milan |
| Orimos.dev S.r.l. | Venice |
| ORMU di Fenini S.p.A. | Parma |
| ORS S.r.l. | |
| Orwell VR | Milan |
| Oval.it | Bergamo |
| Over Holding S.r.l. | Friuli-Venezia Giulia |
| Overbi S.r.l. | |
| Oversonic S.r.l. | |
| Ovolab | Turin |
| OxyTech S.r.l. | Milan |
| P&L Sistemi | Padua |
| P&P Project by Piemme S.r.l.s. | Lucca |
| P.M. Studios S.r.l. | Bari |
| P101 SGR S.p.A. | |
| P2S Elettronica S.r.l. | Vicenza |
| PA Partners Associates S.p.A. | Friuli-Venezia Giulia |
| Pack | Bologna |
| Pagasus Communicazione S.r.l. | Bergamo |
| PagoPA S.p.A. | |
| Pamitron S.r.l. | Trento |
| Pane&Design S.r.l. | Catania |
| Paneura S.r.l. | Friuli-Venezia Giulia |
| Panservice | Latina |
| Pantalia | Naples |
| Panthera S.r.l. | Milan |
| Paperlit S.r.l. | Cagliari |
| Par-Tec | Milan |
| Parco Studio | Milan |
| Park Smart S.r.l. | |
| ParkingMyCar | Perugia |
| Parklab | Milan |
| Parsec Tech S.r.l. | South Tyrol |
| Partech S.p.A. | |
| Partner Data S.r.l. | Milan |
| Pase Web Studio | Treviso |
| Paser S.r.l. | Asti |
| Pat Infinite Solutions | Treviso |