| Decimal | Information Technologies (IT) | decimal.ca |
| Decor Experts Expo Inc | Tout Entreprises et services | decorexpertsexpo.com |
| Decor Trianon Ltée | Clothes Lines | facebook.com |
| Delisle, Gilles | Audiologists | facebook.com |
| Demers Quincaillerie Industrielle | Abrasives | quincailleriedemers.com |
| Denis Dompierre CGA | Accounting Services | ddcga.ca |
| Denis Dompierre CPA M Fisc | Accounting Services | ddcga.ca |
| Denise Couture | Couture, COUTURE | — |
| Dermalissant - Esthétique Et Épilation Longueuil | Beauty & Fitness, Hairdressers & Beauty Salons | — |
| Dermapure Longueuil | Beauty & Health Spas | — |
| Descair | Air Conditioning Contractors | descair.ca |
| Deschamps Patrice | Dentists | facebook.com |
| Descôteaux Huissiers de justice | Bailiffs | facebook.com |
| Design Absolu | Beauty & Fitness, Hairdressers & Beauty Salons | designabsolu.com |
| Design Gilbert Hayart | Architects | designhayart.com |
| Design Raynald Roy | Fitness Gyms | — |
| Desjardins de Longueuil | Banks | — |
| destilino.com | Tout Informatique et internet | destilino.com |
| Destination Niko & Joujou | Children's Clothing Stores | facebook.com |
| Dialogic Corporation | Information Technologies (IT), Tout Informatique et internet | dialogic.com |
| Diane Beauchamp Massotherapeute | Massage Therapy | facebook.com |
| Diocèse de Saint-Jean-Longueuil | Tout Communautés et société | dsjl.org |
| Diocèse Saint-Jean-Longueil | Churches & Other Places of Worship | dsjl.org |
| Directo Service De Comptabilité Et De Gestion Au x Entreprises | Bookkeeping Software & Accounting Systems | — |
| Discount Car and Truck Rentals | Car Rental | — |
| Distribution Polycrete Mntrl | Building Contractors | facebook.com |
| Distributrice Automatique Ben Inc | Coffee Wholesalers | facebook.com |
| Diva Auto Inc | Car Repair | — |
| Doigts de fées | Beauty & Fitness, Hairdressers & Beauty Salons | facebook.com |
| Dollarama | Tout Commerces au détail, Candles | dollarama.com |
| Domaine d'Iberville Apartments | Apartment Rental, Apartments | bwalk.com |
| Domaine D'Iberville Ltée | Apartment Rental, Apartments | bwalk.com |
| Don Design | Tout Commerces au détail | dondesign.chez.com |
| Dotemtex | Tout Entreprises et services | dotemtex.ca |
| Dotemtex Recherche de Cadres Inc. | Tout Entreprises et services | dotemtex.ca |
| Dr André Nguyen | Dentists | — |
| Dr Bernard Couturier | Medical Clinics | facebook.com |
| Dr Dominic Beauchemin | Chiropractors | facebook.com |
| Dr François Auger | Chiropractors | — |
| Dr Jean-Yves Sirois | Dentists | cliniquednetairesirois.com |
| Dr Rejean Begin | Medical Clinics | — |
| Dr. Lussier-Morin Annie-Claude | Dentists | facebook.com |
| Dr. Saife Muhsin Dmd | Dentists | — |
| Dre Mélie Lavigueur Lachance | Dentists | — |
| Drenlia Inc. | Computer & Technology Assistance Programs | drenlia.com |
| Dubé & Tétreault CPA S E N C R L | Bookkeeping | — |
| Duong Thong Pharmacien | Pharmacy | — |
| Duoson Multimedia Inc | Audiovisual Equipment & Supplies, Audiovisual Equipment & Supplies Rental | duoson.com |
| Duvet Etc | Bedding & Linens | — |
| Dynastie Royale | Beauty & Fitness, Hairdressers & Beauty Salons | shekinahair.com |
