| Oslo Linux User Group | Oslo |
| Oslo Metropolitan University | |
| Oslo Perl Mongers | Oslo |
| Oslo Pils and Linux Users Group | Oslo |
| Oslo universitetssykehus | Oslo |
| Oslo universitetssykehus | |
| OstomyCure AS | |
| OTee AS | |
| Otovo | |
| Otovo AS | |
| Otrum AS | Oslo |
| OwnersRoom | |
| Pandion Energy AS | |
| Pangea Accelerator | |
| Patentstyret | |
| Pattern Recognition Systems AS | Hordaland |
| PC Support AS | Møre og Romsdal |
| PcFixer'n | Vestfold |
| PCI Biotech | |
| Penny Venture | |
| PeopleUknow | |
| Pharmasum Therapeutics AS | |
| Phonero | Vest-Agder |
| Photocure ASA | |
| Picterus AS | |
| Pinovo AS | |
| Piscada AS | |
| Pistachio | |
| PixEdit | Vestfold |
| Pixotope | |
| Plaace | |
| Planktonic AS | |
| Playfinity | |
| Playpulse AS | |
| poLight AS | Vestfold |
| Pre Diagnostics AS | |
| Predator | Vestfold |
| Presail | |
| Prevas | Oslo |
| Prima Regnskap | |
| PRO ISP | Rogaland |
| Pro Well Plan | |
| Programutviking | |
| Promis AS | Oslo |
| Promon | |
| Propely AS | |
| ProperHost.com | Vest-Agder |
| PROSA Security AS | |
| Protex AS | |
| ProVenture AS | Trøndelag |