| Open Ocean Robotics | |
| Open Path Partners | |
| Open People Network | |
| Open Storage Solutions | Ontario |
| OPEN Technologies | |
| Open Text Corporation | Ontario |
| Open Universal Software, Inc. | Quebec |
| Open Waters Solar | |
| Openbox Solutions, Inc. | Ontario |
| OpenBSD | Alberta |
| Opencell Biomedical | |
| OpenConnect Internet | Alberta |
| Openframe Technologies, Inc. | Quebec |
| OpenMind Technologies | Quebec |
| OpenNet Initiative | Ontario |
| OpenNorth | Quebec |
| OpenPlus.ca | Ontario |
| Opensoft, Inc. | Ontario |
| OpenSports | |
| OpenSRS | Ontario |
| OPEQ | Quebec |
| Operatrix Consulting, Inc. | |
| Opermax Canada, Inc. | |
| Opersys | Quebec |
| Operto Guest Technologies | |
| OPES Software | Quebec |
| Opid Technologies | Ontario |
| Opiia | Ontario |
| OPIN Digital | Ontario |
| Opioapp.com | |
| OPIsystems, Inc. | Alberta |
| Oplim | |
| OpportunitiesNB | New Brunswick |
| Oprim | Ontario |
| Oproma, Inc. | Quebec |
| OPSEC | Ontario |
| Opsens Solutions | |
| OpsLevel | |
| Opslock | |
| Opsun Systems, Inc. | Quebec |
| OPTASY | |
| Optasy | |
| Optech | Quebec |
| Optel Group | Quebec |
| Optemo Technologies | |
| Opterus, Inc. | |
| Opticca Consulting | |
| Opticomm Marketing | |
| Optiflo | |
| Optik360 | Quebec |