| | Organization Name(s) | Located In |
 | M and M Residence for Seniors | Barrie |
 | MacLeod Services | Orillia |
| | MADD Canada, Barrie Simcoe Chapter | Barrie |
 | MADD Canada. National Office | Oakville |
 | Malton Community Information Service | Malton |
 | Manito Shrine Club. Collingwood | Clearview |
 | Manulife Financial | Toronto |
 | Maple Valley Sports Bar | Penetanguishene |
 | Maplewood Retirement Residence | Penetanguishene |
| | March of Dimes Canada, Summer Holiday Program | Barrie |
 | March of Dimes Canada (London), Home and Vehicle Modification Program | London |
| | Mariposa Writers' Group | Orillia |
| | Marlene's Foot Care | Wasaga Beach |
 | Martyrs' Shrine | Tay |
 | Masala Integrative Lifecare | Tay |
 | Massage Rx, Registered Massage Therapy, Ronda-Lynne Wiesner, RMT | Midland |
 | Matyas Consulting Inc | Midland |
 | Maurice's Valu-Mart, Home Delivery Service | Midland |
 | Mavrou Chiropractic Services | Midland |
 | Mayer's Martial Arts. Elmvale | Elmvale |
 | Mayer's Martial Arts. Victoria Harbour | Victoria Harbour |
 | Mayer's Martial Arts. Victoria Harbour, Hombu Dojo | Victoria Harbour |
 | McArthur's Berry Farm | Oro-Medonte |
 | McClure (Dr Douglas) | Midland |
 | McCraken Psychotherapy | Severn |
 | Meadow Creek Montessori School | Barrie |
 | Meals On Wheels, Alliston | Alliston |
 | Meals on Wheels, Angus | Barrie |
| | Meals On Wheels, Innisfil | Innisfil |
 | Mediation Centre of Simcoe County Inc | Barrie |
 | Medichair Barrie | Barrie |
 | Mehta (Dr. Shardul) | Midland |
 | Mental Health and Addiction Services of Simcoe County, Assertive Community Treatment Team | Barrie |
 | Mental Health and Addiction Services of Simcoe County, Barrie Office | Barrie |
 | Mental Health and Addiction Services of Simcoe County, CARAH House Crisis Services, Mental Health Crisis Line | Barrie |
| | Mental Health and Addiction Services of Simcoe County, CARAH House Crisis Services, Residential Crisis Beds | Barrie |
 | Mental Health and Addiction Services of Simcoe County, Case Management | Barrie |
 | Mental Health and Addiction Services of Simcoe County, Community Awareness Program | Barrie |
 | Mental Health and Addiction Services of Simcoe County, Early Psychosis Intervention | Barrie |
 | Mental Health and Addiction Services of Simcoe County, Housing Support | Barrie |
| | Mental Health and Addiction Services of Simcoe County, Human Services Justice System Program | Barrie |
 | Mental Health and Addiction Services of Simcoe County, Midland Satellite Office | Midland |
 | Mental Health and Addiction Services of Simcoe County, RSVP Clubhouse | Barrie |
 | Mental Health Consumer Survivor Project for Simcoe County | Collingwood |
 | Mental Health Consumer Survivor Project for Simcoe County, People Supporting People | Collingwood |
 | Mermigis (Dr Lambros) Psychologist | Barrie |
| | Mete (Laurie), Certified Foot Care. North Simcoe & Barrie | Minesing |
 | Metis Nation of Ontario, Aboriginal Healing and Wellness Program | Midland |
 | Metis Nation of Ontario, Aboriginal Healthy Babies, Healthy Children | Midland |
 | Metis Nation of Ontario, Georgian Bay Metis Council | Midland |
 | Metis Nation of Ontario Education and Training | Midland |
| | Midhurst Arts and Crafts Home Tour (The) | Midhurst |
 | Midhurst Bridge Club | Midhurst |
 | Midhurst Ratepayers Association | Midhurst |
 | Midhurst Tennis Club | Midhurst |
 | Midhurst United Church | Midhurst |
 | Midland Alliance Church | Midland |
| | Midland and District Business Women's Association | Midland |
 | Midland and District Lawn Bowling Club | Midland |
| | Midland Area Newcomers Club | Midland |
 | Midland Badminton Program | Midland |
 | Midland Bay Sailing Club | Midland |
 | Midland Chiropractic Clinic | Midland |
 | Midland Civitan Club | Midland |
 | Midland Civitan Club, Medical Equipment Loan Program | Midland |
 | Midland Cultural Centre Inc | Midland |
 | Midland Curling Club | Midland |
 | Midland Denture Clinic | Midland |
 | Midland District Camera Club | Midland |
 | Midland District Kennel and Obedience Club | Midland |
 | Midland District Railroad Club (The) | Tiny |
 | Midland District Shrine Club | Midland |
 | Midland Drive-In Theatre | Midland |
 | Midland Duplicate Bridge Club | Midland |
| | Midland Farmers & Artisans Market | Midland |
| | Midland Fibromyalgia Group | Midland |
 | Midland Flyers Jr C Hockey Team | Midland |
 | Midland Golf and Country Club | Midland |
| | Midland Hiking Club (The) | Midland |
 | Midland Horticultural Society | Midland |
 | Midland Keegos Aquatic Club | Midland |
 | Midland Ladies Softball League | Perkinsfield |
| | Midland Lions Club | Midland |
 | Midland Lodge of Independent Order of Odd Fellows 274 | Midland |
 | Midland Lodge of Independent Order of Odd Fellows 274, Medical Equipment Loan Program | Midland |
| | Midland Minor Baseball Association | Midland |
 | Midland Minor Hockey Association | Midland |
 | Midland Minor Lacrosse Association | Midland |
 | Midland Mountainview Family Co-operative Inc | Midland |
 | Midland Nursery School | Midland |
 | Midland Physiotherapy and Rehabilitation Centre | Midland |
| | Midland Power and Sail Squadron | Midland |
 | Midland Power Utility Corporation | Midland |
 | Midland Public Library | Midland |
 | Midland Public Library, Authors Series | Midland |
 | Midland Secondary School | Midland |
 | Midland Secondary School Scholarship Fund | Midland |
 | Midland Senior Citizens Club 160 | Midland |
| | Midland Shuffleboard Club (The) | Midland |
 | Midland Ski Club | Midland |
 | Midland Small Set Co-op Nursery School | Midland |
 | Midland Sports Hall of Fame | Midland |
 | Midland Spring Home Show | Midland |
 | Midland Volleyball Club | Midland |
| | Midland Women's Ball Hockey League | Midland |
| | Midland, Penetanguishene and District Builders Association | Midland |
 | Midland, Town of. Department of Parks and Recreation, North Simcoe Sports and Recreation Centre | Midland |
 | Midland, Town of. Department of Parks, Recreation and Culture, Midland Town Dock | Midland |
 | Midland, Town of. Department of Parks, Recreation and Culture, Pete Petersen Park. Boat Launching Facility | Midland |
 | Midland, Town of. Fire Department | Midland |
 | Midland, Town of. Midland Police Service | Midland |
 | Midland, Town of. Midland Seniors Council | Midland |
 | Midland, Town of. Midland Transit Service | Midland |
 | Midland, Town of. Midland Transit Service, Accessible Transit, Community Reach | Midland |
 | Midland, Town of. Municipal Office | Midland |
 | Midland, Town of. Parks and Recreation Department | Midland |
 | Midland-Penetanguishene District Community Emergency Response Team | Midland |
| | Midland-Penetanguishene Field Naturalists | Midland |
 | Midwives Nottawasaga | Collingwood |
 | Mikey's Place for Autism Resource Centre | Midland |
 | Mill Creek Care Centre, Long Term Care Facility | Barrie |
 | Minds Alive | Midland |
 | Minesing Central Public School | Minesing |
 | Minesing Community Association | Minesing |
 | Minesing Minor Ball Association | Minesing |
 | Minesing United Church | Minesing |
| | Ministry of Children and Youth Services, Ontario, United Way of Greater Simcoe County, Eat Well to Excel. Simcoe County | Simcoe County |
 | Ministry of Community Safety and Correctional Services, Ontario Fire Marshall - Southwest Region | Midhurst |
 | Ministry of Economic Development and Innovation, Simcoe Muskoka Office | Midhurst |
 | Mirror (The) | Midland |
 | Mission Church of St Louis de France. Mount St. Louis | Oro-Medonte |
| | Mitchell's Medical Supply Inc. | Midland |
 | Mnjikaning Kendaaswin School Age Program | Rama |
| | Mobile Seating and Mobility Clinics, PT Health Providing Healthcare Solutions | Midland |
 | Mobility Centre Plus | Midland |
 | Monsignor Castex Elementary School. Midland | Midland |
| | Mood Disorders Support Group of Barrie | Barrie |
| | Moonglow | Elmvale |
 | Moonstone Elementary | Oro-Medonte |
 | Morgan (Michael J), Private Tutoring | Midhurst |
 | Mortgage Centre (The), Collingwood Location, Christmas Hamper Program | Collingwood |
 | MotherCare Barrie | Barrie |
 | MotherCare Barrie Next Step Program | Barrie |
 | MotherCare Innisfil | Innisfil |
 | MotherCare Innisfil Next Step Program | Innisfil |
 | Mothercare North Simcoe, Community Action Program for Children / Canada Prenatal Nutrition Program, Catulpa Community Support Services Inc. | Midland |
 | Motherisk, Info Line and Clinic | Toronto |
 | Mount Lakeview Non Profit Housing Corporation | Midland |
 | Mountainview Cycling Club | Midland |
 | Mountainview Ski Area | Midland |
 | MTM Conservation Association Incorporated, Tiny Marsh Provincial Wildlife Area, Marl Lake, Matchedash Bay | Tiny |
 | MTN Communications Systems | Midland |
 | Multicultural History Society of Ontario | Toronto (City of) |
 | Multiple Sclerosis Society of Canada, Simcoe County Chapter | Barrie |
 | Multiple Sclerosis Society of Canada, Simcoe County Chapter, Midland Self Help/Exercise Group | Midland |
 | Mundy's Bay Public School. Midland | Midland |
 | Municipal Property Assessment Corporation, Simcoe County, Municipal Assessment Office #16, Property Assessment Program | Barrie |
| | Muscular Dystrophy Canada, Simcoe Region Chapter of Muscular Dystrophy | Simcoe County |
 | Music For Young Children, Orillia | Orillia |
 | Music Therapy Services of Simcoe County | Barrie |
 | Muskoka Wildlife Centre | Severn |
| | My Friend's House | Collingwood |