| 2430 | Man-made fibres and filaments (except cellulosic), manufacturing | |
| 2430 | Man-made fibres and filaments, manufacturing | |
| 5149 | Man-made fibres, wholesale | |
| 1711 | Man-made filament yarn, throwing, twisting, texturizing or winding purchased yarn | |
| 1711 | Man-made staple spun yarns, made from purchased fibre | |
| 7499 | Mannequin decorating service | |
| 3699 | Mannequins, manufacturing | |
| 5150 | Mannequins, wholesale | |
| 2429 | Mannitol hexanitrate explosive materials, manufacturing | |
| 3313 | Manometers, industrial process type, manufacturing | |
| 7491 | Manpower employer services, federal | |
| 7491 | Manpower employer services, provincial government | |
| 7491 | Manpower pools | |
| 7491 | Manpower program, federal (job placement) | |
| 4540 | Mantel work (stone) installation | |
| 2022 | Mantels, wood, manufacturing | |
| 1729 | Mantles, incandescent, manufacturing | |
| 5020 | Manual transmission repair and replacement, motor vehicle service | |
| 3420 | Manufactured (mobile) buildings for commercial use (e.g., banks, offices), manufacturing | |
| 3420 | Manufactured (mobile) buildings, non-residential, manufacturing | |
| 3420 | Manufactured (mobile) classrooms, manufacturing | |
| 3420 | Manufactured (mobile) homes, manufacturing | |
| 4020 | Manufactured gas production and distribution | |
| 5122 | Manufactured tobacco products, wholesale | |
| 9111 | Manufacturers' associations | |
| 4520 | Manufacturing buildings, construction | |
| 5150 | Manufacturing industry machinery and equipment, wholesale | |
| 7414 | Manufacturing operations improvement consulting services | |
| 4520 | Manufacturing plants (light industrial), construction | |
| 5240 | Manuscripts, rare, retail | |
| 7421 | Map drafting services | |
| 1542 | Maple products production, central facility | |
| 0112 | Maple products production, on the farm | |
| 0112 | Maple sap, gathering of | |
| 1542 | Maple sugar and syrup, production (except on farms) | |
| 5122 | Maple sugar and syrup, wholesale | |
| 0112 | Maple sugar bush, operating | |
| 0112 | Maple sugar production, on farm | |
| 0112 | Maple syrup production, on farm | |
| 0112 | Maple taffy production, on farm | |