| Ocean Software Solutions | |
| Ocean Sonics | Nova Scotia |
| Ocean Startup Project | Nova Scotia |
| Ocean Technology Council of Nova Scotia | |
| Ocean Tracking Network | |
| Oceanic Computer Tech Service, Inc. | |
| Oceanic Wind Energy, Inc. | British Columbia |
| OceansAdvance, Inc. | |
| Ocelot Computer Services, Inc. | Ontario |
| Ockam Web Design | Quebec |
| Ockham Consulting | British Columbia |
| OCM Manufacturing, Inc. | Ontario |
| OCPR | British Columbia |
| OCR Canada | Ontario |
| OCRI Global Marketing | Ontario |
| Octacom Ltd | Ontario |
| Octagon Systems | |
| Octasic | Quebec |
| Octav | |
| Octopus Creative, Inc. | |
| Octopus-ITSM.com, Inc. | Quebec |
| Octothorpe Software | British Columbia |
| Octothorpe Software Corporation | |
| ODAIA Intelligence, Inc. | |
| Odan Laboratories Ltd | |
| Odata Solutions | Ontario |
| Oddex | |
| Oddly Studios | Ontario |
| Odegi | Ontario |
| Odel Group | Ontario |
| Odesia | Quebec |
| Odesia Decision, Inc. | Quebec |
| Odiwi Canada | |
| ODL Designs | Ontario |
| Odynet | Ontario |
| Odynet, Inc. | Ontario |
| Odyssey 3D | |
| Odyssey Computers | British Columbia |
| OE Canada, Inc. | |
| OES Manufacturing | |
| OES, Inc. | Ontario |
| Offering Helper | British Columbia |
| Office Imaging PowerEdge Group | Ontario |
| Office IRC, Inc. | Ontario |
| Office of the Information and Privacy Commissioner for B.C. | British Columbia |
| Office of the Information and Privacy Commissioner Newfoundland and Labrador | Newfoundland and Labrador |
| Office of the Information and Privacy Commissioner of Alberta | Alberta |
| Office of the Nunavut Information and Privacy Commissioner | Northwest Territories |
| Office of the Privacy Commissioner of Canada | |
| Office of the Saskatchewan Information and Privacy Commissioner | Saskatchewan |