| MacLachlan College, Oakville - Lower School Campus, Pre-Kindergarten to Grade 6 Program | Oakville |
| MacLachlan College, Oakville - Upper School Campus, Grade 7 to Grade 12 Program | Oakville |
| Madina Institute Canada, Oakville, Madina Programs | Oakville |
| Main Care Pharmacy and Clinic, Milton, Walk-in Clinic | Milton |
| 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, March of Dimes Canada Employment Services Hamilton Office, Integrated Employment Services | Hamilton |
| March of Dimes Canada (GTA), Toronto - Duncan Mill, SkillingUp | Toronto |
| Marketplace Medical Centre, Walk-in Clinic and Family Practice | Milton |
| MAWI Medical Clinic, Family Practice and Walk-in Clinic | Oakville |
| Maximize Your Health - Mississauga Halton Self Management Program, Oakville | Oakville |
| May Court Club of Oakville (The) | Oakville |
| MedEvac Canada, Air and Ground Patient Transfer Service | Mississauga |
| Media Smarts, Ottawa - Online/Web Service | Ottawa |
| Medical Transportation, Non-emergency, Halton Region | Halton Region |
| MedicAlert Foundation Canada, MedicAlert Program | Toronto |
| Melanoma Canada | Oakville |
| 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 |
| Metrolinx | Toronto |
| Mi3L School, Robotics and STEM Programs | Oakville |
| Midwives of Brampton and Halton Hills, Midwifery Services | Brampton |
| Midwives of Mississauga | Erin Mills |
| Millhouse Resthome, Halton Hills, Group Home | Halton Hills |
| Millhouse Resthome, Acton, Group Home | Acton |
| Milton Autism | Milton |
| Milton Badminton Club, Recreational Badminton | Milton |
| Milton Bible Church, Community Food Programs | Milton |
| Milton BMX Racing | Milton |
| Milton Chamber of Commerce | Milton |
| Milton Chinese Canadian Association | Milton |
| Milton Community Resource Centre | Milton |
| Milton Community Resource Centre, Milton - Viola Desmond Public School, EarlyON Child and Family Centre | Milton |
| Milton Community Resource Centre, EarlyON Child and Family Centre | Milton |
| Milton Community Resource Centre, Food for Life Community Fridge | Milton |
| Milton Concert Band | Milton |
| Milton Curling Club | Milton |
| Milton Family Care Centre, Family Practice and Walk-in Clinic | Milton |
| Milton Girls Softball | Milton |
| Milton Health Centre, Walk-in Clinic | Milton |
| Milton Heights Ski Racing Club | Milton |
| Milton Kendo Club | Milton |
| Milton Lawn Bowls | Milton |
| Milton Life Care, Addiction Services | Milton |
| Milton Marlin Swim Team | Milton |
| Milton Minor Ball Hockey League | Milton |
| Milton Minor Hockey Association | Milton |
| Milton Minor Lacrosse Association | Milton |
| Milton Philharmonic Orchestra | Milton |
| Milton Pickleball Association | Milton |
| Milton Players Theatre Group | 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 Sea Cadets, Milton - RCSCC Chaudiere, 304 Royal Canadian Sea Cadet Corps Chaudiere | Milton |
| Milton Skating Club | Milton |
| Milton Speed Skating Club | Milton |
| Milton Springers Gymnastics Club | Milton |
| Milton Stags Youth Basketball | Milton |
| Milton Tennis Club | Milton |
| Milton Trails Medical Clinic and Walk-In | Milton |
| Milton Transitional Housing | Milton |
| Milton United Soccer Club | Milton |
| Milton Urgent Care Clinic | Milton |
| Milton Youth Soccer Club | Milton |
| Milton Youth Volleyball Club | 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 Sports Centre, Milton Youth Space | Milton |
| Milton. Community Services, Milton Sports Centre, Recreation Facilities & Programs | Milton |
| Milton. Community Services, Adult Recreation Programs | Milton |
| Milton. Community Services, Children and Youth Recreation Programs | Milton |
| Milton. Community Services, Financial Assistance for Recreation Programs | Milton |
| Milton. Community Services, Inclusion for Special Needs | Milton |
| Milton. Community Services, School Breaks and After School Recreation Programs | Milton |
| Milton. Community Services, Outdoor Sports Parks | Milton |
| Milton. Community Services, Parks and Trails | Milton |
| Milton. Community Services, Multiple Locations, Splash Pads | 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. Transit | Milton |
| Milton. Transit, Milton access+ | Milton |
| Mind Forward Brain Injury Services, Mississauga - Head Office | Mississauga |
| Mint Care Clinic | Oakville |
| Mission Services of Hamilton, Inasmuch House Women's Shelter Services | Hamilton |
| Mission Thrift Store | Burlington |
| Mississauga Women's Clinic | Cooksville |
| Mississauga, City of, MiWay Transit | Mississauga |
| MitoCanada Foundation | Oakville |
| Mobility Aids and Assistive Equipment, Halton Region | Halton Region |
| Mobility Medical Transportation | Oakville |
| Mood Disorders Association of Ontario, Peer Supports and Services | Toronto |
| Mosaic Foundation for Youth and Women | Burlington |
| Mountainview Medical Centre and Walk-In Clinic | Georgetown |
| Movies for Mommies Oakville, The Original Parent & Baby Film Event | Oakville |
| MS Canada | Toronto Downtown Central |
| MusFit, Sports Programs for Youth and Adults | Oakville |
| Muslim Association of Milton, Oakville - Halton Islamic Community Centre, Cultural Heritage Group | Oakville |
| Muslim Association of Milton, MAM Food Bank | Milton |
| Muslim Children's Aid and Support Services, Child, Youth and Family Support Services | Toronto |
| My Community Services, My Community Services, Mississauga West | Mississauga |
| Myasthenia Gravis Society of Canada | Ontario |
