| Dance Ability Movement (The), Milton - Dance Elite Studio | Milton |
| Dar Foundation, Oakville | Oakville |
| Dar Foundation, Oakville, Food Program | Oakville |
| Dare to be Youth Charity | Burlington |
| Darling Home for Kids | Milton |
| Dawn of Angels Health | Burlington |
| DeafBlind Ontario Services | Newmarket |
| Dearcroft Montessori School, Oakville | Oakville |
| Dearcroft Montessori School, Oakville, 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, Retirement Residence | Oakville |
| Derry Pharmacy | Milton |
| Designated Driving Services - Companies Serving Halton | Halton Region |
| Destiny Care Services | Mississauga |
| Developmental Services Ontario Central West Region, Halton Office - Milton | Milton |
| Diabetes Canada, D-Camps Ontario | Huntsville |
| Diabetes Canada | Toronto Downtown Central |
| 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, No Physical Address | Ottawa |
| Doctor's Office Urgent Care Clinic | Burlington |
| Dog Rescuers | Oakville |
| Dolphins Swim Club, Oakville | Oakville |
| Doris Care Services | Mississauga |
| Dorval Medical Family Health Team | Oakville |
| Downtown Acton Business Improvement Area | Acton |
| Downtown Acton Business Improvement Area, Actons Farmers Market | Acton |
| Downtown Georgetown Business Improvement Area | Georgetown |
| Downtown Georgetown Business Improvement Area, Downtown Georgetown Farmers' Market | Georgetown |
| Downtown Milton Business Improvement Area | Milton |
| Downtown Oakville Business Improvement Area, Oakville | Oakville |
| Dr. Bob Kemp Hospice, Centre for Hospice Palliative Care | Hamilton |
| Dreams to Memories Foundation | Fort Erie |
| Drew Hildebrand Teen Benefit Fund | Mississauga |
| DriveAgain, Burlington, Driver Assessment Services | Burlington |
| DriveTest Centre, Burlington | Burlington |
| Drivetest Centre, Oakville | Oakville |
| DriveTest Centre, Guelph | Guelph |
| Drury Lane Theatrical Productions | Burlington |
| Dundas Neyagawa Medical Centre and Pharmacy | 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 |
| Dynes Christian Centre, Mailing Address | Burlington |
| Dystonia Medical Research Foundation Canada | Toronto Downtown West |
