| Name | Region |
|---|---|
| Oncorena AB | |
| OncoZenge | |
| OncoZenge AB | |
| OnDosis AB | |
| One Wave | |
| One-Carbon Therapeutics AB | |
| Oneflow AB | |
| Onelab AB | |
| OnePartnerMedia | |
| OnePhone Holding AB | |
| Onslip Cloud AB | |
| OPEN | |
| Open Payments Europe AB | |
| OpenGeeksLab | |
| Öpensöurce AB | Stockholm |
| Opsy AB | |
| Optise AB | |
| Optronic | Västerbotten |
| Opus Group AB | |
| Oracle Sverige | Stockholm |
| Orange Lamp Software Solutions | Västmanland |
| Orangelab AB | |
| Orderhero | |
| Ordna AB | |
| Örebro universitet | Örebro |
| Örestad Linux | Skåne |
| Orexo AB | |
| OrganAise | |
| Orisoft AB | Stockholm |
| Ormaco AB | |
| OssDsign AB | |
| Osstell | |
| Östgöta Tele-System AB | Östergötland |
| Osystem AB | Skåne |
| OurGreenCar Sweden AB | |
| Outby AB | |
| Outfox Intelligence AB | Stockholm |
| Outpost24 | Blekinge |
| Overkill Software | |
| Oversite AB | Stockholm |
| Ovulai AB | |
| Ovzon AB | |
| OX2 | |
| Oxceed | |
| Oxcia AB | |
| Oxide AI | |
| Oxion Biologics AB | |
| OxThera AB | |
| Oy DL Software Ab | |
| P&K TimeApp AB |