| Aquarius Tropical Fish | Aquariums & Supplies | aquariusweb.qc.ca |
| AquaSense Workshop | Aquariums & Supplies | — |
| Aquatech Société de Gestion de l'Ea... | Tout Entreprises et services | aquatech-quebec.ca |
| Aquatech, Societé de gestion de l'eau | Life Sciences and Health Technologies (LSHT) | aquatech-inc.com |
| Aquateck Inc. | Tout Entreprises et services | aquateck.com |
| Aquatica Digital | Tout Entreprises et services | aquatica.ca |
| AquaZone Aquarium Services | Aquariums & Supplies | aquazoneaquariumservices.ca |
| Aquazul Décontamination | Home Improvement | aquazul.ca |
| Aquila Communications Inc. | Tout Entreprises et services | aquilacommunications.com |
| Ar Vargas | Cleaning Services, Cleaning Service | — |
| ARA Productions | Audiovisual Production Services | araproductions.com |
| ARA robotique | Information Technologies (IT) | ara-uas.com |
| ARA Roboyique | Information Technologies (IT) | ara-uas.com |
| ARAHOVA SOUVLAKI MILE-END | Home Decoration & Maintenance | arahova.com |
| ARAHOVA SOUVLAKI ST-LAURENT | Home Decoration & Maintenance | arahova.com |
| ARAHOVA SOUVLAKI – SIÈGE SOCIAL | Home Decoration & Maintenance | arahova.com |
| Aralia | Landscaping | araliadesign.com |
| ARAMARK Québec Inc. | Tout Entreprises et services | aramark.ca |
| Aramark Refreshments | Beverage Distributors & Bottlers | aramarkrefreshments.com |
| Aramis Vitres d'Autos | Auto Glass & Windshields | facebook.com |
| Araz Technique Electrique | Electricians | facebook.com |
| ARB Teck et Specialites | Tout Commerces au détail | arbteak.com |
| Arboriculture J L | Landscaping | — |
| Arborite | Tout Entreprises et services | arborite.com |
| ARC Electrique Inc | Electricians | — |
| Arc-Thac Services | Electricians | — |
| Arcade MTL | Amusement Places, Arcades, Tout Bars et restaurants | arcademtl.com |
| Arcadia Eastman | Bed & Breakfasts | — |
| Arch | Architects | — |
| Archak A. | Home Improvement | — |
| Archambault | Book Stores | facebook.com |
| ARCHANGELS Greek Orthodox Comm. | Blue Pages | — |
| Arche de Dieu | Clergy | interarche.org |
| Arches Perspectives | Architectural Drawing | ericsson.com |
| Archipel architecture | Tout Entreprises et services | archipel-architecture.ca |
| Architect Montreal | Architects | architectmontreal.com |
| Architecte Maxime Brault | Architects | maximebrault.com |
| Architecte Nicolas Blais | Architects | facebook.com |
| Architectes Bertrand Paquette | Architects | facebook.com |
| Architecture Baccanale | Architectural & Construction Specifications | — |
| Architecture Inform | Architectural Technologists | — |
| Architecture pour Tous | Architects | ap2.ca |
| Architecture49 | Architects | arcop.com |
| Archive Contemporary | Art Galleries, Dealers & Consultants | — |
| ARCHIVE NATIONALES DU QUEBEC | Blue Pages | anq.gouv.qc.ca |
| Archives de la Ville de Montréal | Tout Informations générales | flickr.com |
| Archives de Montréal | Tout Enseignement et savoir | archivesdemontreal.com |
| Archives municipales | Not Profit, library | archivesdemontreal.com |
| Archivex | Business Centres | facebook.com |
| Arcoiris Massage Therapy | Massage Therapy | arcoiris.ca |
