| Micro Scalp Clinic Montreal | Westmount | Beauty & Fitness, Hairdressers & Beauty Salons |
| Miel Sisters | Westmount | Boutiques |
| Mishkin Seymour Dr | Westmount | Health Services |
| Miss Brown's Cleaning Services Westmount | Westmount | Cleaning Services, Cleaning Service |
| Miss Edgar's and Miss Cramp's Schoo... | Westmount | Tout Enseignement et savoir |
| MNC Multinational Consultants | Westmount | Business Brokers |
| Mochico | Westmount | Boots |
| Monstres Textiles Enr | Westmount | Calendars |
| Montreal Art School | Westmount | Art Schools |
| Montreal Camera Club | Westmount | Tout Arts et divertissement, Tout Communautés et société |
Publicité (Desktop) Publicité (Mobile) |
| Montreal Children's Dental Clinic | Westmount | Health Services |
| Montreal Sleep Center | Westmount | Health Services |
| Monty's Hair Salon | Westmount | Beauty & Fitness, Hairdressers & Beauty Salons |
| Morris & MacKenzie Inc | Westmount | Car Insurance |
| Mouton Noir | Westmount | Caterers |
| Mperia Therapeutics | Westmount | Life Sciences and Health Technologies (LSHT) |
| Mperia Therapeutics Inc. | Square | Life Sciences and Health Technologies (LSHT) |
| Multi Energy R.H.H. International Inc | Westmount | Boutiques |
| My Shoe Shop Montreal Store | Westmount | Boots |
| Myschoolofjoy | Westmount | Astrologers & Psychics |
Publicité (Desktop) Publicité (Mobile) |
| MyX Therapeutics (anciennement Eosinate Therapeutics) | Square | Life Sciences and Health Technologies (LSHT) |
| National Restoration | Westmount | Roofing |
| NETTOYEURS DAOUST | Westmount | Clothing |
| NETTOYEURS DAOUST | Westmount | Clothing |
| NOVA Montréal | Westmount | Care Homes |
| Npc | Westmount | Computer Repair & Cleaning |
| Office for Science and Society | Westmount | Tout Enseignement et savoir |
| Oliver Thomas L Dr | Westmount | Dentists |
| Omnident Services Limited | Westmount | Dentists |
| Optimal Group Inc | Westmount | Accounting Services |
Publicité (Desktop) Publicité (Mobile) |
| Optimal Payments | Westmount | Information Technologies (IT) |
| Ordre des infirmières et infirmiers... | Westmount | Tout Communautés et société, Tout Entreprises et services |
| Orenstein Law | Westmount | Business Lawyers |
| Orthosport Canada Inc. | Westmount | Tout Commerces au détail |
| P.A. Services Conseils Inc. | Westmount | Tout Entreprises et services |
| Padgett Services Aux Entrepris | Westmount | Bookkeeping Software & Accounting Systems |
| Palmistry Center | Westmount | Astrologers & Psychics |
| Paysagement Déneigement John Mastro | Westmount | Landscaping |
| Paysagiste Malik | Westmount | Landscaping |
| PDQ 12 - SPVM (Ville-Marie Ouest, Westmount - Poste de quartier 12 - Service de Police de la Ville de Montréal - SPVM) | Westmount | Emergency |
Publicité (Desktop) Publicité (Mobile) |
| Pearl White Solutions Westmount | Westmount | Dentists |
| Perma Culture Garden | Westmount | Landscaping |
| Pharmacie Emna Mzabi Inc, Westmount Square | Westmount | Pharmacy |
| Phases & Cycles Inc | Westmount | Animal Shelters & Protection Services |
| Photos of the Attractive Nature in Canada | Westmount | Landscaping |
| Physio Veneta Stolinchev | Westmount | Physiotherapy |
| Pilaflex Studio | Westmount | Beauty Salon Equipment & Supplies |
| Plomberie Westmount | Montréal | Plumbing |
| Positive Inc | Westmount | Bank Equipment & Supplies |
| Pragmatic Communications | Westmount | Communications & Public Relations Consultants |
