| Main Care Pharmacy and Clinic, Milton, Pharmacy Services | Milton |
| Main Care Pharmacy and Clinic, Milton, Walk-in Clinic | Milton |
| Main Street Pharmacy, Pharmacy Services | Milton |
| Maple Avenue Baptist Church | Georgetown |
| Maple Grove United Church | Oakville |
| Maple Medical Pharmacy, Pharmacy Services | Milton |
| Maple Mews Medical Clinic, Walk-in Medical Clinic | Burlington |
| Maple Mews Pharmacy, Pharmacy Services | Burlington |
| Maple Villa Long Term Care Centre, Long Term Care Home | Burlington |
| Maranatha Homes | Burlington |
| March of Dimes Canada, Oakville - Jean and Howard Caine Apartments, Supportive Housing Program - Attendant Care Services | Oakville |
| March of Dimes Canada, Burlington / North Halton Branch, Attendant Services | Burlington |
| March of Dimes Canada, Home and Vehicle Modification Program | London |
| March of Dimes Canada, West Central Regional Office, After Stroke Program | Milton |
| March of Dimes Canada (GTA), Community Support Services (Toronto) | Toronto |
| Mariposa Cooperative Homes | Oakville |
| Marketplace Medical Centre, Walk-in Clinic and Family Practice | Milton |
| Marketplace Pharmacy, Pharmacy Services | Milton |
| Mary Mother of God Parish | Oakville |
| Masjid Noor-UL-Haram | Oakville |
| Masterworks of Oakville Chorus & Orchestra | Oakville |
| MaxCare Medical Centre | Oakville |
| Maximize Your Health - Mississauga Halton Self Management Program | Oakville |
| Medcare Pharmacy, Pharmacy Services | Oakville |
| Medexpress Pharmacy, Pharmacy Services | Burlington |
| Medical Image Wigs | Oakville |
| Medical Laboratories, Burlington | Burlington |
| Medical Laboratories, Halton Hills | Halton Hills |
| Medical Laboratories, Milton | Milton |
| Medical Laboratories, Oakville | Oakville |
| Medical Transportation, Non-emergency, Halton Region | Halton Region |
| MedicAlert Foundation Canada | North York East |
| Medicare Pharmacy, Pharmacy Services | Oakville |
| Medicine Shoppe (The), Pharmacy Services | Burlington |
| Medicine Shoppe (The), Milton - 400 Main St E, Pharmacy Services | Milton |
| Medicine Shoppe (The), Oakville, Pharmacy Services | Oakville |
| MedNation Home Healthcare, Medical Equipment and Supplies | Oakville |
| MedProDirect - Your Incontinence Specialist | Mississauga |
| MedSleep, Respirology and Sleep Medicine | Milton |
| Melanoma Canada | Oakville |
| Memory & Company, Oakville Club, Retirement Residence, Respite and Adult Day Program | Oakville |
| Mental Health Commission of Canada | Ottawa |
| Mental Health Mutual-Aid Hub Canada, Mandarin Hotline and Mental Health Support | Toronto |
| Métis Nation of Ontario, Toronto Regional Office | Toronto Downtown East |
| Métis Nation of Ontario, Brampton | Brampton |
| Métis Women's Circle, Métis Women's Circle Programs and Events | Hamilton |
| Metro Pharmacy, Burlington - Appleby Line, Pharmacy Services | Burlington |
| Metro Pharmacy, Georgetown, Pharmacy Services | Halton Hills |
| Metro Pharmacy, Milton, Pharmacy Services | Milton |
| Metro Pharmacy, Oakville - North Service Rd W, Pharmacy Services | Oakville |
| Metro Pharmacy, Oakville - Upper Middle Rd E, Pharmacy Services | Oakville |
| Metrolinx | Toronto |
| Milestone Health Services, In Home Care Services | Milton |
| Millcroft Pharmacy, Pharmacy Services | Burlington |
| Millhouse Resthome, Halton Hills, Group Home | Halton Hills |
| Millhouse Resthome, Acton, Group Home | Acton |
| Milton & District Horticultural Society | Milton |
| Milton Active Oldstars Hockey Club | Milton |
| Milton Badminton Club, Recreational Badminton | Milton |
| Milton Baptist Church | Milton |
| Milton Bible Church | Milton |
| Milton Bible Church, Community Food Programs | Milton |
| Milton Bible Fellowship | Milton |
| Milton Chinese Arts Society, Mailing Address | Milton |
| Milton Chinese Association | Milton |
| Milton Choristers | Milton |
| Milton City Church (New World Ministries) | Milton |
| Milton Community Resource Centre, Community Fridge | Milton |
| Milton Concert Band | Milton |
| Milton Curling Club | Milton |
| Milton Family Care Centre, Family Practice and Walk-in Clinic | Milton |
| Milton Health Centre, Walk-in Clinic | Milton |
| Milton Historical Society | Milton |
| Milton Historical Society, Waldie Blacksmith Shop and Carriage Room | Milton |
| Milton Ladies Slo Pitch, Recreational Baseball League | Milton |
| Milton Ladies Softball League | Milton |
| Milton Life Care, Addiction Services | Milton |
| Milton Life Care Pharmacy, Pharmacy Services | Milton |
| Milton Meals on Wheels | Milton |
| Milton Mens Basketball | Milton |
| Milton Old Friends League, Over 50 Slo-Pitch League | Milton |
| Milton Philharmonic Orchestra | Milton |
| Milton Pickleball Association | Milton |
| Milton Players Theatre Group | Milton |
| Milton Pleasure League | Milton |
| Milton Public Library, Main Branch, Library Services | Milton |
| Milton Public Library, Beaty Branch, Library Services | Milton |
| Milton Public Library, Sherwood Branch, Library Services | Milton |
| Milton Red Sox Senior Baseball Club | Milton |
| Milton Santa Claus Parade Committee, Milton Santa Claus Parade | Milton |
| Milton Skating Club | Milton |
| Milton Sports Hall of Fame | Milton |
| Milton Square Pharmacy, Pharmacy Services | Milton |
| Milton Tennis Club | Milton |
| Milton Trails Medical Clinic and Walk-In | Milton |
| Milton Transitional Housing | Milton |
| Milton Urgent Care Clinic | Milton |
| Milton Youth Soccer Club | Milton |
| Milton. Community Services, FirstOntario Arts Centre Milton | Milton |
| Milton. Community Services, John Tonelli Sports Centre, Recreation Facilities & Programs | Milton |
| Milton. Community Services, Mattamy National Cycling Centre, Recreation & Cycling Facilities & Programs | Milton |
| Milton. Community Services, Memorial Arena, Arena Facilities & Recreational Programs | Milton |
| Milton. Community Services, Milton Leisure Centre, Recreation Facilities & Programs | Milton |
| Milton. Community Services, Milton Seniors' Activity Centre | Milton |
| Milton. Community Services, Milton Seniors' Activity Centre, Older Adults Recreation Programs | Milton |
| Milton. Community Services, Milton Sports Centre, Recreation Facilities & Programs | Milton |
| Milton. Community Services, Outdoor Sports Parks | Milton |
| Milton. Community Services, Parks and Trails | Milton |
| Milton. Community Services, Nassagaweya Tennis Centre and Community Hall, Tennis Recreation Programs & Community Facilities | Milton |
| Milton. Community Services, Recreational Skating | Milton |
| Milton. Community Services, Sherwood Community Centre, Recreation Facilities & Programs | Milton |
| Milton. Community Services, Swimming | Milton |
| Milton. Corporate Services, Property Tax Information | Milton |
| Milton. Fire and Rescue Services | Milton |
| Milton. Fire and Rescue Services, Community Education Programs | Milton |
| Milton. Operations Department, Windrow Snow Removal Program | Milton |
| Milton. Planning and Development, Heritage Planning | Milton |
| Milton. Town Council | Milton |
| Milton. Town Council, Milton Town Hall, Mayor - Gordon Krantz | Milton |
| Milton. Town Council, Milton Town Hall, Ward 1 Regional Councillor - Colin Best | Milton |
| Milton. Town Council, Milton Town Hall, Ward 1 Town Councillor - Kristina Tesser Derksen | Milton |
| Milton. Town Council, Milton Town Hall, Ward 2 Regional Councillor - Rick Malboeuf | Milton |
| Milton. Town Council, Milton Town Hall, Ward 2 Town Councillor - John Challinor II | Milton |
| Milton. Town Council, Milton Town Hall, Ward 3 Regional Councillor - Sammy Ijaz | Milton |
| Milton. Town Council, Milton Town Hall, Ward 3 Town Councillor - Adil Khalqi | Milton |
| Milton. Town Council, Milton Town Hall, Ward 4 Regional Councillor - Sameera Ali | Milton |
| Milton. Town Council, Milton Town Hall, Ward 4 Town Councillor - Sarah Marshall | Milton |
| Milton. Town Hall | Milton |
| Milton. Transit | Milton |
| Milton. Transit, Milton access+ | Milton |
| Miltowne Pharmacy | Milton |
| Mind Forward Brain Injury Services | Mississauga |
| Mind Forward Brain Injury Services, Adult Day Program | Oakville |
| Mint Care Medical Centre and Walk In Clinic | Oakville |
| Mint Care Pharmacy, Pharmacy Services | Oakville |
| Mission Services of Hamilton, Inasmuch House Women's Shelter Services | Hamilton |
| Mission Services of Hamilton, Mission Services of Hamilton, Men's Shelter Services | Hamilton |
| Mississauga Halton Central West Regional Cancer Program, Trillium Health Partners - Credit Valley Hospital - Carlo Fidani Regional Cancer Centre | Mississauga |
| Mississauga Halton Central West Regional Cancer Program, Oakville Trafalgar Memorial Hospital, Cancer Care Clinic | Oakville |
| Mississauga Halton Central West Regional Cancer Program, Trillium Health Partners - Credit Valley Hospital - Carlo Fidani Regional Cancer Centre, Diagnostic Assessment Program (DAP) | Mississauga |
| Mississauga Halton Centre for Complex Diabetes Care, Complex Diabetes Care | Oakville |
| Mississauga Halton Palliative Care Network | Mississauga |
| Mississauga Institute for Neurological Disorders and Stroke (MINDS) | Erin Mills |
| Mississauga, City of, MiWay Transit | Mississauga |
| Mississauga, City of, NSTAL - Huron Park Recreation Centre, Next Step to Active Living, Adult Day Program | Mississauga |
| Mixed Company Theatre | Toronto |
| Mobile Denture Services | Etobicoke Central |
| Mobility Aids and Assistive Equipment, Halton Region | Halton Region |
| Mobility Medical Transportation | Oakville |
| Moderation Management | Oakville |
| Mood Disorders Association of Ontario | Toronto |
| Morelli's, Oakville - Wyecroft Rd, Pharmacy Services | Oakville |
| Morelli's, Oakville - Cornwall Rd, Pharmacy Services | Oakville |
| Morelli's, Oakville - Dundas St E, Pharmacy Services | Oakville |
| Mount Nemo Christian Nursing Home, Long Term Care Home | Burlington |
| Mountain Grove Christadelphians | Burlington |
| Mountainview Residence, Care Wing - Assisted Living | Georgetown |
| Mountainview Terrace | Halton Hills |
| MS Canada | Toronto Downtown Central |
| Municipal Property Assessment Corporation, Online Service, Find a Municipal Property Assessment Corporation Office | |
| Munn's United Church | Oakville |
| Museums of Burlington, Joseph Brant Museum | Burlington |
| Museums of Burlington, Ireland House Museum | Burlington |
| Muslim Advisory Council of Canada, Oakville | Oakville |
| Muslim Association of Milton, Cultural Heritage Group | Oakville |
| Muslim Community Services, Muslim Community Services, Mississauga West | Mississauga |
| My Grandfather's Cat, No Physical Address - Online Service | |
| Myasthenia Gravis Society of Canada | Ontario |
