| Organization Name(s) | Located In |
| Do Not Call List | Ottawa |
| D-TEK-TION Security Systems Inc | Barrie |
| Dadswell Denture Clinic | Collingwood |
| Daguiam [Dr G] Family Dentistry | Orillia |
| Dalrymple and Countryside Seniors | Carden |
| Dalrymple United Church | Ramara |
| Dalston United Church | Oro-Medonte |
| Dalston-Crown Hill United Church. Crown Hill Location | Oro-Medonte |
| Dalston-Crown Hill United Church. Dalston Location | Springwater |
| Dalton [Sandy] | Barrie |
| Dance Connection (The) | Tottenham |
| Dance Mania | Alliston |
| Dance Workshop (The) | Alliston |
| Danceroom Dance Studio (The) | Stayner |
| Dancers Studio (The) | Midland |
| Dancers Studio (The), DANCEcamp | Midland |
| Daniel [Dr P] | Orillia |
| Dann [John] French Tutoring and Translation | Barrie |
| Danube Seniors Leisure Centre | Bradford |
| Dar's Stars of Music | Barrie |
| Daughters of Isabella | Penetanguishene |
| Dave Chun Guitar Studio | Barrie |
| David Busby Street Centre | Barrie |
| Davidson [Dr Thomas] | Midland |
| Dawna's Caring Touch | Alliston |
| De La Roca, Jennifer Counselling Service | Barrie |
| Deacon Taws | Midland |
| Deaf Access Simcoe Muskoka, Advocacy and Accessibility Education | Barrie |
| Deaf Access Simcoe Muskoka, Barrie Central Office | Barrie |
| Deaf Access Simcoe Muskoka, Employment Services | Barrie |
| Deaf Access Simcoe Muskoka, General Support Services | Barrie |
| Deaf Access Simcoe Muskoka, Message Relay Assistance | Barrie |
| Deaf Access Simcoe Muskoka, Muskoka Office | Bracebridge |
| Deaf Access Simcoe Muskoka, Sign Language Classes | Barrie |
| Deaf Access Simcoe Muskoka, Sign Language Interpreting | Barrie |
| Deaf Access Simcoe Muskoka, Technical Device Assistance | Barrie |
| DeafBlind Ontario Services | Newmarket |
| Decoration Day. United Civic Memorial | Orillia |
| Dedicated Dads for Young Fathers. Orillia | Orillia |
| DeGasperis [Joanne] | Stayner |
| Deimling [Dr J P] | Orillia |
| Delf's Martial Arts & Health Club | Bradford |
| Demiray [Ayla] | Barrie |
| Dentistry by the Bay | Midland |
| Depression Support Group | Stayner |
| Depressive and Manic Depressive Association of Ontario. Midland/Penetanguishene and Area | Midland |
| Devil's Glen Country Club | Clearview |
| Dheda [Dr Roshan] | Bradford |
| Dickinson [Dr Bruce] | Innisfil |
| Dietitians of Canada | Ontario |
| Dinners by Design | Midland |
| Discover the Path | Creemore |
| Discovery Child Care Centre, Nursery School Program | Barrie |
| Discovery Child Care Centre. Big Bay Point Rd | Barrie |
| Discovery Child Care Centre. Harvie Rd | Barrie |
| Discovery Harbour | Penetanguishene |
| Dispensary (The) | Bracebridge |
| Diversity Studio and Gallery | Perkinsfield |
| DiVito Denture Clinic | Bradford |
| Doane House Hospice | Newmarket |
| Doctors Office, Armstrong [Dr G], McIntosh [Dr], Odlozinski [Dr], Perrigo [Dr] | Orillia |
| Dolezel [Dr Josef] | Midland |
| Dominion Gospel Hall | Orillia |
| Don't Stand Alone Foundation for Children with Autism | Barrie |
| Donald [Dr Douglas] | Midland |
| Door (The), Collingwood | Collingwood |
| Door (The). Alliston | Alliston |
| Door (The). Clearview | Stayner |
| Dorvict Home and Health Care Services, Barrie | Barrie |
| Double Door Studios and Gallery | Springwater |
| Double Trouble. Support Group | Midland |
| Douglas & Quilty Chartered Accountants | Midland |
| Doula C.A.R.E Inc, Simcoe County Region | Simcoe County |
| Doula CARE Simcoe and Dufferin County | Alliston |
| Doula Services, Labour and Delivery Service | Midland |
| Down Syndrome Association of Ontario | Ottawa |
| Downtown Barrie Business Association | Barrie |
| Downtown Dispensary | Orillia |
| Downtown Midland Business Improvement Area | Midland |
| Downtown Orillia Management Board | Orillia |
| Dowswell Family Chiropractic & Wellness Centre | Orillia |
| Dr Beth's Chiropractic Clinic & Bioflex Laser Therapy | Collingwood |
| Dr. Peggy Wong | Orillia |
| Dr. Shawn Moore | Orillia |
| Dr. Susy Lee & Associates | Oro Station |
| DriveTest Orillia | Orillia |
| DriveTest/Serco Des Inc, Driver Examination Centre, Barrie | Barrie |
| Drug Store (The). Zehrs | Orillia |
| DRUGStore Pharmacy. Gagnon's Independent | Bracebridge |
| DRUGStore Pharmacy. Terry's Independent | Gravenhurst |
| Drury's Helping Hands Inc | Wasaga Beach |
| Dubeau's Farm | Perkinsfield |
| Duck Soup Productions | Orillia |
| Ducks Unlimited Canada, Barrie Chapter | Barrie |
| Ducks Unlimited Canada. Collingwood Chapter | Collingwood |
| Ducks Unlimited Canada. Orillia Chapter | Orillia |
| Dufferin Hi-Land Bruce Trail Club (The) | Alliston |
| Duffers by the Water | Barrie |
| Duhamel [Dr Paul] | Collingwood |
| Dunkerron United Church | Bradford West Gwillimbury |
| Dunn Dentistry [Dr Stephen] | Alliston |
| Duntroon Central Public School | Clearview |
| Duntroon Day Care Inc. | Clearview |
| Duntroon Highlands Golf Club. Recreational Leagues | Clearview |