| 9141-2148 Québec Inc | Westmount | Cleaning Services, Cleaning Service |
| ABP Consultants en personnel | Westmount | Tout Entreprises et services |
| Abrasive Technology N A Inc | Dorval | Abrasives, Tout Entreprises et services |
| ABZ Assurances-Insurance | Westmount | Car Insurance |
| ACA | Westmount | Collection Agencies |
| Acadia | Montréal | Computer & Technology Assistance Programs |
| Acadia | Montréal | Computer & Technology Assistance Programs |
| Académie Ballet Flamenco Lina Moros | Westmount | Tout Enseignement et savoir |
| Accenture | Montréal | Information Technologies (IT) |
| ACCEO Solutions | Montréal | Information Technologies (IT), Tout Informatique et internet |
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| Acces Physio Collège Charles-Lemoyne | Delson | Physiotherapy |
| Acier Wirth Steel | Westmount | Aluminum |
| Action Sport Physio | Westmount | Tout Entreprises et services, Physiotherapy |
| Acupuncteure Certifiée Pascale Tremblay | Delson | Acupuncturists |
| Adelman, Adam | Westmount | Boutiques |
| Adl Esthétique Automobile | Delson | Car Detailing |
| ADP Canada R-L | Montréal | Information Technologies (IT) |
| Advanceit Financial Corp | Montréal | Computer Networking |
| Advanceit Financial Corp | Westmount | Computer Networking |
| Aiguisatek | Delson | Tout Entreprises et services |
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| AIR RESEARCH TECHNOLOGY INC. | Montréal | Aerospace |
| Air-Therm Inc | Westmount | Plumbing |
| Alipro-Mistral Ingrédients Inc | Delson | Agri-food |
| Altea Furniture | Westmount | Antique Restoration, Refinishing & Repair |
| AM1280 CFMB | Westmount | Tout Médias montréalais |
| Amadea S. Kezar Physiothérapie | Westmount | Physiotherapy |
| AmorChem Holdings Inc | Montréal | Life Sciences and Health Technologies (LSHT) |
| AmorChem Therapeutics Inc | Westmount Square | Life Sciences and Health Technologies (LSHT) |
| Andrea Flütsch | Westmount | Physiotherapy |
| Antiquites Coach House Enr | Westmount | Antique Dealers |
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| Apex Performance | Delson | Fitness Gyms |
| Aplast Canada Inc | Westmount | Home Improvement |
| AQUACOUPE TECHNOLOGY INC. | Mirabel | Aerospace |
| AquaExpert | Westmount | Aquariums & Supplies |
| Ari Financial Services Inc | Laval | Car Leasing |
| Aroua Tek Inc | Delson | Appliance Manufacturers & Wholesalers |
| Artgold Fine Art Inc | Westmount | Antique Dealers |
| Aréna | Delson | Arenas, Stadiums & Athletic Fields |
| Aspler Joseph Jutras Inc | Westmount | Car Insurance |
| Assemblage Assembletout | Delson | Assembly & Fabricating Services |
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| Assemblée Quaker de Montréal | Westmount | Tout Communautés et société |
| Assima Canada / Wizart Canada | Montréal | Information Technologies (IT) |
| Association des Médecins omnipratic... | Westmount | Tout Communautés et société |
| Association des Éditeurs de Langue... | Westmount | Tout Entreprises et services |
| Asus | Montréal | Computer & Technology Assistance Programs |
| Atelier Blow | Westmount | Beauty & Fitness, Hairdressers & Beauty Salons |
| Atelier de Serrures Martin's Swiss | Westmount | Bicycle Stores |
| Atelier Scissor House | Westmount | Beauty & Fitness, Hairdressers & Beauty Salons |
| Atrium Innovations Inc. | Westmount | Agri-food |
| Autocar Jeannois Inc | Delson | Bus Stations & Ticket Agencies |
