| OutReach Media | Ontario |
| OutreachGenius | |
| Outshine Online | Nova Scotia |
| Outside in the sun | British Columbia |
| Outside The Box | |
| Outsite The Box | |
| Outsource IT Computing, Inc. | Ontario |
| Outsource Web Design | British Columbia |
| Outsourced Marketing | |
| Outstrip.ca | Ontario |
| Outwest Design | British Columbia |
| OVA | Quebec |
| OVA | |
| Ovaltel, Inc. | Quebec |
| Ovation Science, Inc. | |
| Ovensa, Inc. | |
| OverActive Media | Ontario |
| Overactive Media Group | |
| Overbond | Ontario |
| Overdrive | Ontario |
| Overhaul Media | Alberta |
| Overlay TV | Ontario |
| OVH Hosting | Quebec |
| Ovislink Canada, Inc. | Ontario |
| Owl Labs, Inc. | |
| Owl Practice, Inc. | |
| OWL Timeclock | Ontario |
| Owlet Baby Care, Inc. | |
| Ownr | |
| OWS Systems Solutions | Ontario |
| OXD | British Columbia |
| Oxford Cancer Analytics | |
| Oxford Consulting Group Ltd | Ontario |
| Oxio | Quebec |
| Oxygen Technologies | Manitoba |
| OZ Optics Ltd | Ontario |
| OZ Video Games | Quebec |
| Oznogco | Quebec |
| P & P Data Systems, Inc. | Ontario |
| P&O Expert, Inc. | |
| P&P Data Systems, Inc. | Ontario |
| P&P Optica | Ontario |
| P&T IT Brother | Ontario |
| P-DELTA | |
| P. Lecavalier Consulting | Ontario |
| P.C. Consulting | Ontario |
| P.C. Dictation Systems Ltd | |
| P.C. Medic Computers, Inc. | Ontario |
| P.P. Informatique | Quebec |
| P.S. Informatique | |