| OpenHR | Madrid |
| openTrends Solucions i Sistemes, S.L. | Barcelona |
| OpenVidu | Madrid |
| OPEX Informática | Madrid |
| Optare Solutions | Pontevedra |
| Optima Solutions | Madrid |
| Optimaweb | |
| Optimoclick | Barcelona |
| Optimus Price | Barcelona |
| Optimus, S.A. | Girona |
| OPTYMA - Proveedores de Presencia en Internet, S.L. | Madrid |
| Oracle Spain | Madrid |
| Orange España | Madrid |
| Orbit Consulting Group, S.L. | Madrid |
| Orbyn, S.L. | Madrid |
| Orca | Valencia |
| Ordatic | Valencia |
| Organic Boosting | Valencia |
| Organización Nacional de Trasplantes | |
| Origami Soluciones | Pontevedra |
| Oroi Wellbeing, S.L. | Gipuzkoa |
| Orquest | Madrid |
| Oryzon Genomics, S.A. | Barcelona |
| Osés RFID, S.L. | Navarre |
| Outvise | Barcelona |
| Over The Top Games | Barcelona |
| Overalia | Gipuzkoa |
| Oversight | Santa Cruz de Tenerife |
| OWO | Málaga |
| Ozono Multimedia, S.L.L. | A Coruña |
| P4Q | Biscay |
| Paack | Barcelona |
| Pacific Computers - Herrador Informática, S.L. | Madrid |
| PAL Robotics, S.L. | Barcelona |
| Palo BioFarma | Barcelona |
| Pampua | Alicante |
| Panda Security | Biscay |
| Pandorahub | Barcelona |
| Pangaea Oncology | Barcelona |
| Pangea Aerospace | Barcelona |
| ParatuPc.es | Ciudad Real |
| Parc Cientific de Barcelona | Barcelona |
| Parc Científic de la Universitat de València | Valencia |
| Parc Científic i Tecnològic de Girona | Girona |
| Pariver, S.A. | Zaragoza |
| Parque Cientifico y Tecnologico Cartuja, S.A. | Sevilla |
| Parque Tecnológico de Andalucía | Málaga |
| Parsec Media, S.L. | |
| Parsec SYS, S.L. | Cantabria |
| Payflow Digital Inc Sucursal en España | Barcelona |