| MacLaren Art Centre, Centre d'art MacLaren | Barrie |
| MacLaren Art Centre, Cours d'art et camps de jour pour enfants et jeunes | Barrie |
| MacTier Food Bank, MacTier, Banque alimentaire de MacTier | Georgian Bay Township |
| Magic of Children in the Arts, Magie des enfants dans les arts | Collingwood |
| Maing (Dr Dianne) Psychologue | Barrie |
| Mains LeReseaudaideauxfamilies.ca, Inactif Bureau de Parry Sound, Bureau de Parry Sound | Parry Sound |
| Maison de retraite Champlain Manor | Orillia |
| Maison de retraite Terrace Simcoe, LOFT at Simcoe Terrace | Barrie |
| Maison de retraite Terrace Simcoe | Barrie |
| Maisons coopératives Angus | Essa |
| Making Change, Aucune adresse physique | Barrie |
| Manito Shriner's Club | Clearview (Comté Simcoe) |
| Manna Food Bank of Bracebridge, Banque alimentaire Manna de Bracebridge | Bracebridge |
| Maplehill Wellness, Barrie, Soin des pieds | Barrie |
| Maplehill Wellness | Wasaga Beach |
| March of Dimes Canada, Barrie, Services de lésion cérébrale acquis - Groupes d'activités de sensibilisation dans le comté de Simcoe | Barrie |
| March of Dimes Canada, Collingwood, Homemaking, Collingwood | Collingwood |
| March of Dimes Canada, Collingwood, Services d'aide à la vie autonome et services à faible acuité - Programme de vie autonome, Collingwood | Collingwood |
| March of Dimes Canada, Midland, Homemaking, Collingwood | Midland |
| March of Dimes Canada, Midland, Services d'aide à la vie autonome et services à faible acuité - Programme de vie autonome, Collingwood | Midland |
| Marche des dix sous Canada (RGT) | Toronto |
| Marché fermier de Barrie | Barrie |
| Marek (Dr Ken) Psychologist Lifegates Unlimited, Dr Ken Marek, Psychologue | Barrie |
| Marlene's Foot Care | Clearview (Comté Simcoe) |
| Matthews House, Unité de soins palliatifs communautaire | New Tecumseth |
| Matthews House Hospice, Soins palliatifs résidentiels | Alliston |
| May Court Club of Barrie, Club May Court de Barrie | Barrie |
| May Court Club of Barrie, Magasin May Court | Barrie |
| Meadow Creek Montessori School, West, Meadow Creek Montessori School, Meadow Creek Montessori School East | Barrie |
| Meaford. Bureau municipal, Services d'incendie de Meaford | Meaford |
| Meals On Wheels, Alliston, Popote roulante | New Tecumseth |
| Mediation Centre of Simcoe County, Centre de médiation du comté de Simcoe | Barrie |
| Melville Presbyterian Church, Église presbytérienne de Melville | Huron Est |
| Mermigis (Dr Lambros) Psychologist | Barrie |
| Mete (Laurie Ann), Soins avancés des pieds certifiés | Springwater |
| Metis Nation of Ontario, Bureau de Barrie, Services domiciliaires Infinity - Programme de logement rural autochtone | Barrie |
| Métis Nation of Ontario, Midland, Metis Healthy Babies, Healthy Children | Midland |
| Michela McConnell Psychotherapy & Consulting Services, Orillia, Psychothérapie et service de conseil | Orillia |
| Midland Midwives By the Bay | Midland |
| Midland Midwives By the Bay, Sages-femmes Midland Midwives By the Bay | Midland |
| Midland Mountainview Family Co-operative, Inc | Midland |
| Midland Power Utility Corporation | Midland |
| Midland Public Library, Bibliothèque publique de Midland Public Library | Midland |
| Midland Town Crier, Crieur public de Midland | Midland |
| Midland, Town of., Midland - Bayshore Dr, Service d'incendie | Midland |
| Midland, Town of., Midland - Dominion Ave, Bureau municipal | Midland |
| Milverton Christian Fellowship | Perth Est |
| Minden Hills. Bureau municipal, Minden - 12418, route 35, Services d'incendie et d'urgence | Minden |
| Minesing United Church, Église Unie Minesing | Minesing |
| Ministère du Solliciteur général, Orillia, Probation et libération conditionnelle, Orillia | Orillia |
| Mission Thrift Store - Barrie, Friperie Mission - Barrie | Barrie |
| Modern College of Hairstyling and Esthetics, Collège moderne de coiffure et d'esthétique | Barrie |
| Molson Sportsmen Hockey League, ligue de hockey Molson Sportsmen | Barrie |
| Mom's 4 Mom's Doula Services, Pas d'adresse physique, Service de doula Mom's 4 Mom's Doula Services | Oro-Medonte |
| Mood Disorders Association of Ontario | Toronto |
| Morgentaler Clinic (The) | Toronto Centre-ville Nord |
| Mortgage Centre (The), Programme de paniers de Noël | Collingwood |
| Moulin Microcrédits | Toronto |
| MTM Conservation Association Incorporated, MTM Conservation Association, Réserve faunique provinciale de Tiny Marsh | Tiny |
| Mulcaster Mews | Barrie |
| Multiple Births Canada, Naissances multiples Canada | Richmond Hill |
| MultiSport Canada | Barrie |
| Murray's Windermere Gardens | Barrie |
| Musée centenaire et Archives de Penetanguishene, Penetanguishene Centennial Museum | Penetanguishene |
| Musée Coldwater | Severn |
| Musée Huronia et village Huron-Ouendat | Midland |
| Musée militaire de la Base Borden | |
| Museum on the Boyne | New Tecumseth |
| Music Therapy Services of Simcoe County, Services de musicothérapie du comté de Simcoe | Barrie |
| Muskoka Algonquin Healthcare, Emplacement de l'hôpital South Muskoka Memorial, Programme de dépistage du cancer du sein de l'Ontario | Bracebridge |
| Muskoka Algonquin Healthcare, Inactif Bracebridge - 75 Ann St, Seniors Assessment and Support Outreach Team | Bracebridge |
| Muskoka Algonquin Healthcare, Inactif Bracebridge - 75 Ann St, South Muskoka Memorial Hospital Site | Bracebridge |
| Muskoka Indigenous Friends Cultural Centre, Muskoka Indigenous Friendship Centre | Gravenhurst |
| Muskoka Lakes Museum, Musée de Muskoka Lakes | Muskoka Lakes Township |
| Muskoka Residential Centre, Centre résidentiel Muskoka | Severn |
| Muskoka Seniors, Muskoka Seniors Home Assistance | Huntsville |
| Muskoka Small Business Centre | Bracebridge |
| My Friend's House, Refuge pour victimes de violence familiale | Collingwood |
| My Pre Academy | Barrie |
| My Sister's Place, Inactif People in Transition (Alliston) Inc., My Sister's Place | New Tecumseth |