| Marsnet | British Columbia |
| MARSWorks, Inc. | Ontario |
| Martal Group | |
| Martello Technologies | Ontario |
| Martin Behrens | British Columbia |
| Martin Decelles | Quebec |
| Martina Iring | British Columbia |
| MaRuche | |
| Marvel & Snap | Ontario |
| Marvel Biosciences Corporation | |
| Marwick Marketing | |
| Mary Agrotechnologies | |
| Mary Read Design Studio | Ontario |
| Mascon | British Columbia |
| Mash | |
| Mashup Lab | |
| Maskatel | Quebec |
| Mason Graphite, Inc. | |
| MASS Engineered Design, Inc. | Ontario |
| Mass Mobile Apps | Ontario |
| Mass5 | Ontario |
| Massive Web Design, Inc. | Ontario |
| Massively | |
| Massmédia Web | Quebec |
| Master Software Solutions | |
| MasterDev Technologies, Inc. | British Columbia |
| Masterfile Corporation | Ontario |
| Mastermind Solutions, Inc. | |
| Mastermynde Strategy, Inc. | British Columbia |
| Masterpiece Studio | |
| Masterpiece Studio | |
| Masters Computers | Ontario |
| MasterSEO | Ontario |
| Mastervox Électronique | |
| Masthead | |
| MASV Media | |
| MAT SEO | |
| Matacs | Ontario |
| Matayo | |
| Matchstick, Inc. | Ontario |
| Math Central | Saskatchewan |
| Math Master | Ontario |
| Math Vault | |
| Mathost.com | Quebec |
| MathResources, Inc. | Nova Scotia |
| Matias | Ontario |
| Matidor Technologies | |
| Matiss | |
| Matissoft | |
| Matrikon | Alberta |