| Dance Ability Movement (The) | Milton |
| DaNurse, In Home Care Services | Etobicoke |
| Dar Foundation | Oakville |
| Dar Foundation, Food Program | Oakville |
| Dare to be Youth Charity | Burlington |
| Darling Home for Kids | Milton |
| Dawn of Angels Health, In Home Care Services | Burlington |
| Deaf Muslims of Canada, Interpretation / Translation | Burlington |
| DeafBlind Ontario Services | Newmarket |
| Dearcroft Montessori School | Oakville |
| Dearcroft Montessori School, Oakville - Dearcroft Trafalgar Crossing, Licensed Child Care Centre | North Oakville |
| Dearcroft Montessori School, Oakville - Lakshore Rd E, Licensed Child Care Centre | Old Oakville |
| Dearcroft Montessori School, Oakville - Rebecca St, Licensed Child Care Centre | Oakville |
| DEBRA Canada | Oakville |
| Debtors Anonymous | Oakville |
| Debtors Anonymous | Toronto Downtown Central |
| Deliverance Tabernacle Church of God | Burlington |
| Delmanor Glen Abbey, Oakville, Retirement Residence | Oakville |
| Dental Hygiene Practioners of Ontario, Online / Web Service, Find a Dental Hygienist | Ontario |
| Derry Pharmacy, Pharmacy Services | Milton |
| Destiny Care Services, In Home Care Services | Mississauga |
| Developmental Services Ontario Central West Region, Single Point of Access for Adult Developmental Services | Milton |
| Diabetes Canada | Toronto Downtown Central |
| Diabetes Canada, D-Camps Ontario | Huntsville |
| Diagnostic Imaging, Halton Hills | Halton Hills |
| Diagnostic Imaging, Oakville | Oakville |
| Dietitians of Canada | Toronto Downtown Central |
| Dietitians of Canada - UnlockFood.ca | Toronto Downtown Central |
| directSmiles, Mobile Dental Hygiene Services | Oakville |
| Distress and Crisis Ontario | Waterloo |
| Distress Centre Halton | Halton Region |
| Distress Centres of Greater Toronto, Survivor Support Program, Toronto Office | Toronto |
| Divorce Canada | Ottawa |
| Doctors House Call Service - Concierge Medicine, In Home Doctor Services | Burlington |
| Doctor's Office Urgent Care Clinic, Walk-in Medical Clinic | Burlington |
| Dog Rescuers Inc (The) | Oakville |
| Dolphins Swim Club | Oakville |
| Dorval Medical Family Health Team | Oakville |
| Downtown Acton Business Improvement Area | Acton |
| Downtown Acton Business Improvement Area, Downtown Acton Outdoor Market / Acton Leathertown Festival | Acton |
| Downtown Georgetown Business Improvement Area | Georgetown |
| Downtown Georgetown Business Improvement Area, Georgetown Farmers' Market | Georgetown |
| Downtown Milton Business Improvement Area | Milton |
| Downtown Oakville Business Improvement Area | Oakville |
| Dr. Bob Kemp Hospice, Hospice and Palliative Care | Hamilton |
| Dreams to Memories Foundation | Fort Erie |
| Drew Hildebrand Teen Benefit Fund | Mississauga |
| DriveAgain, Driver Assessment Services | Burlington |
| DriveTest Centre, Burlington, Driver Examination Centre | Burlington |
| DriveTest Centre, Oakville, Driver Examination Centre | Oakville |
| DriveTest Centre, Guelph | Guelph |
| Drury Lane Theatrical Productions | Burlington |
| Dundas Neyagawa Medical Centre, Family Practice and Walk-in | Oakville |
| Dying with Dignity Canada | Toronto |
| Dynacare, Oakville - Old Bronte Rd, Laboratory and Health Services Centre | Oakville |
| Dynacare, Oakville - Bristol Circle, Laboratory and Health Services Centre | Oakville |
| Dynacare, Acton - Eastern Rd, Medical Laboratory Services | Halton Hills |
| Dynacare, Milton, Laboratory and Health Services Centre | Milton |
| Dynacare, Oakville - Oak Park Blvd, Laboratory and Health Services Centre | Oakville |
| Dystonia Medical Research Foundation Canada | Toronto Downtown Central |
