| Norwin A/S | Region Zealand |
| Nosco | |
| Notify Therapeutics ApS | |
| Nova Data | Region of Southern Denmark |
| Novax A/S | Capital Region of Denmark |
| November First A/S | |
| Novicell | |
| Novo Holdings A/S | Capital Region of Denmark |
| Novo Nordisk A/S | |
| Novorésumé ApS | |
| Novozymes | |
| NowOnline | |
| NRGi | |
| NTI A/S | Capital Region of Denmark |
| Nuuday | |
| NXUS ApS | |
| Nykredit | |
| Nørd It | Region Zealand |
| Ocean.io | |
| Octarine Bio | |
| Octopus | Capital Region of Denmark |
| Odico | Region of Southern Denmark |
| OfficeKursus.dk | Capital Region of Denmark |
| OiSTER | Capital Region of Denmark |
| Omada | Capital Region of Denmark |
| OmicVision | |
| Omnigame ApS | |
| Omnio.net ApS | |
| one.com | |
| OneHouse | Region of Southern Denmark |
| OneShop | |
| Online Marketing | Capital Region of Denmark |
| Online WebDesign ApS | Region of Southern Denmark |
| Online-Results A/S | Capital Region of Denmark |
| Onomondo ApS | |
| OnRobot A/S | |
| Op10mer | Central Denmark Region |
| Open Data DK | |
| Open Space Aarhus | Central Denmark Region |
| Openframe ApS | |
| OpenLedger | |
| Opentelehealth ApS | |
| ophavsret PH Cloud Service ApS | |
| Oracle Denmark | Capital Region of Denmark |
| Oracle Konsulent | Capital Region of Denmark |
| Orbis Medicines ApS | |
| ORBIT | |
| Orbit Online A/S | |
| Orbital A/S | |
| Orchestra A/S | |