| McLean Consulting | Ontario |
| McLean Micro | New Brunswick |
| McLean Systems, Inc. | Ontario |
| McLean Watson Venture Capital | Ontario |
| McMaster Innovation Park | Ontario |
| McMaster University | Ontario |
| McMaster University - Department of Computing and Software | Ontario |
| McMaster University - Department of Electrical and Computer Engineering | Ontario |
| McMaster University - Department of Mathematics & Statistics | |
| McMaster University - Department of Mathematics and Statistics | Ontario |
| McMaster University - School of Computational Engineering and Science | Ontario |
| MCN Cabling Ltd | Saskatchewan |
| McQuaig Institute | Ontario |
| McRock Capital | Ontario |
| McRock Capital | |
| MCSNet | Alberta |
| MD Analytics, Inc. | |
| MD Informatique | Quebec |
| MDA | British Columbia |
| MDBilling.ca | Ontario |
| MdeA Services | |
| MDF Commerce | |
| MDG | Ontario |
| MDGRAPHICS | Ontario |
| MDI Solutions | Ontario |
| Mdia-Hosts.com | Ontario |
| MDL Telecom | Ontario |
| MDM Monacoh | Quebec |
| MDMS Managed Digital Media Services, Inc. | New Brunswick |
| MDS Coating Technologies Corporation | |
| MDS Consulting | Ontario |
| MDS Power Canada | Quebec |
| MDT Technical Services, Inc. | British Columbia |
| MDZ IT Solutions, Inc. | Ontario |
| ME Therapeutics | |
| Meade Willis, Inc. | Quebec |
| Mealsy.ca | |
| Meaningful Marketing | |
| Meatec, Inc. | Quebec |
| Mecanica Solutions | Quebec |
| Mecanum, Inc. | Quebec |
| Mecca Internet Solutions | British Columbia |
| Mechasys | |
| MechaTools Technologies | Quebec |
| Mecsmart Systems, Inc. | Ontario |
| Med e-care | |
| MED e-care Healthcare Solutions, Inc. | Ontario |
| Med IT | Ontario |
| Med-Life Discoveries LP | |
| Med2020 | Ontario |