| Name | Region |
|---|---|
| OMG Plant Based Food AB | |
| Omicron Ceti AB | Stockholm |
| Ommej | |
| Ommej AB | |
| Omnio | |
| On 1 Call Support AB | Stockholm |
| Onbaz AB | |
| Once Upon Publishing AB | |
| Oncopeptides AB | |
| Oncopeptides AB | |
| Oncorena AB | |
| Oncorena AB | |
| OncoZenge AB | |
| OnDosis AB | |
| One Wave | |
| One-carbon Therapeutics | |
| Oneflow AB | |
| Onelab AB | |
| OnePhone Holding AB | |
| Onslip Cloud AB | |
| OPEN | |
| Open Payments Europe AB | |
| Öpensöurce AB | Stockholm |
| 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 | |
| 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 | |
| Oxceed | |
| Oxide AI | |
| OxThera AB | |
| Oy DL Software Ab |