| D&K Footcare Mobile Services, Services mobiles de soins des pieds D&K | Bradford West Gwillimbury |
| Danube Seniors Leisure Centre, Centre de loisirs pour personnes âgées Danube | Bradford West Gwillimbury |
| Daughters of Isabella, Penetanguishene, Filles d'Isabella | Penetanguishene |
| David Busby Centre, Barrie, Hébergement collectif d'urgence | Barrie |
| David Busby Centre, Barrie, Programme de fiduciaires volontaires | Barrie |
| David Busby Centre, Barrie, Programmes de sensibilisation | Barrie |
| David Busby Centre, Barrie, Services sans rendez-vous | Barrie |
| David Busby Centre, Collingwood, Services aux sans-abri Out of The Cold | Collingwood |
| Days For Girls, Aucune adresse physique | Barrie |
| Deaf Access Simcoe Muskoka, Barrie Central Office, Accès sourd Simcoe Muskoka, Barrie Central Office | Barrie |
| Deaf Access Simcoe Muskoka, Barrie Central Office, Cours de langue ASL | Barrie |
| Deaf Access Simcoe Muskoka, Barrie Central Office, Interprétation de la langue ASL | Barrie |
| Deaf Access Simcoe Muskoka, Barrie Central Office, Service de soutien communautaire | Barrie |
| Deaf Access Simcoe Muskoka, Barrie Central Office, Services d'emploi | Barrie |
| Défi Atlantique du Canada | Midland |
| Demiray (Ayla) | Barrie |
| Dental Hygiene with Roma | Midland |
| Diabetes Canada | Toronto Centre-ville Centre |
| Diététistes du Canada (Les) | Toronto Centre-ville Centre |
| Diététistes du Canada (Les) - DécouvrezLesAliments.ca | Toronto Centre-ville Centre |
| Discover Wellness, Orillia | Orillia |
| Discovery Child Care Centre, Barrie - chemin Harvie, Garderie, Barrie - chemin Harvie | Barrie |
| Doe Lake Residence, Résidence Doe Lake | Gravenhurst |
| Dominion Gospel Hall | Orillia |
| Donaven Renovations, Lawn Care and Snow Blowing, Mobile Service, Rénovations, entretien de la pelouse et déneigement Donaven | Wasaga Beach |
| Doug's Home and Lawn Care, Mailing address | Wasaga Beach |
| Doula Group (The) | Barrie |
| Doula Services, Labour and Delivery Support, Services Doula, Soutien au travail et à l'accouchement | Midland |
| Down Syndrome Association of Simcoe County, Mailing Address | Barrie |
| Downtown Barrie Business Association (BIA) | Barrie |
| Downtown Dispensary, Dispensaire du centre-ville | Orillia |
| Downtown Midland Business Improvement Area | Midland |
| Downtown Orillia Management Board, Conseil de gestion du centre-ville d'Orillia | Orillia |
| Dr Paul Duhamel, Ordre des psychologues de l'Ontario, Collingwood, Neuropsychologie | Collingwood |
| Dragon Boat Barrie, Mailing Address, bateau-dragon Barrie | Barrie |
| Dress for Success Orillia and Barrie, Barrie, Lutte contre la pauvreté, emploi, Barrie | Barrie |
| Driverseat | Barrie |
| D-TEK-TION Security Systems, Mobile Service, Systèmes de sécurité D-TEK-TION | Barrie |
| Duntroon Day Care, Garderie Duntroon Day Care | |
| Dystrophie musculaire Canada - Bureau régional de l'Ontario | Toronto Centre-ville Nord |