| Office Outfitters Ltd | |
| OfficeBooks | Ontario |
| OfficeSmarts | Manitoba |
| OfficeView Software, Inc. | Ontario |
| Officeworks, Inc. | Newfoundland and Labrador |
| Official Site Builder | |
| Officio | |
| Offshoot | Ontario |
| Offstreet Technology, Inc. | |
| Ogilvie Barsness Financial Group | |
| Ogilvy | Quebec |
| OGMA Consulting Corporation | British Columbia |
| OgoWorks | British Columbia |
| OH! Media | Saskatchewan |
| Ohm Loads, Inc. | Ontario |
| Oil Country Computers | |
| OKAM | Quebec |
| Okanagan College | British Columbia |
| Okanagan College - Department of Computer Science | British Columbia |
| Okanagan College - Department of Mathematics & Statistics | British Columbia |
| OkanaganBCWebHost.ca | British Columbia |
| Okapya Software Solutions | |
| OkaSciences | |
| OKay | Ontario |
| Okidoo Interactif | Quebec |
| Okidoo Interactif, Inc. | Quebec |
| OKIOK | Quebec |
| Okotoks Computers | Alberta |
| Okozaoko | Quebec |
| Oktane | Quebec |
| OkTeck | Quebec |
| OlaTech Corporation | Manitoba |
| Olds College | Alberta |
| Olive Technologies, Inc. | British Columbia |
| Oliver | |
| Oliver POS, Inc. | |
| OLLIP P.C. | Ontario |
| Ollon | |
| Ologix | |
| Olympia Sol4, Inc. | |
| Olympique, solutions informatiques | Quebec |
| Omega Communications Ltd | British Columbia |
| Omega Experts | Quebec |
| Omega Software, Inc. | Ontario |
| Omega Station | British Columbia |
| Omega Venture Group, Inc. | Alberta |
| OmegaChem | |
| Omegawave | |
| Omerlo Technologies, Inc. | Quebec |
| OMERS Ventures | Ontario |