| Nankind | Toronto |
| Nar-Anon Family Groups of Ontario, Barrie - No Physical Address | Barrie |
| Nar-Anon Family Groups of Ontario, Innisfil - Virtual | Innisfil |
| Nar-Anon Family Groups of Ontario, Innisfil | Innisfil |
| Narcotics Anonymous, Georgian Heartland Area | Clearview (Simcoe County) |
| National Association of Federal Retirees, Barrie, National Association of Federal Retirees - Huronia Branch 35 | Barrie |
| National Council of Jewish Women of Canada - Simcoe County, Mailing Address | Innisfil |
| National Student Loans Service Centre | Mississauga |
| Nature Barrie | Barrie |
| Navy League of Canada, Barrie Branch, Barrie - Mailing Address, Royal Canadian Sea Cadet Corps 53 Barrie | Barrie |
| New Democratic Party of Canada, Barrie-Innisfil Federal Electoral District Association | Barrie |
| New Democratic Party of Ontario, No Physical Address, Barrie-Innisfil Provincial Electoral District Association | Barrie |
| New Life Fellowship Baptist Church | Innisfil |
| New Path Youth and Family Services of Simcoe County, Alliston Office, Child and Youth Mental Health Quick Access Clinic | New Tecumseth |
| New Path Youth and Family Services of Simcoe County, Alliston Office, Youth and Family Counselling Services | New Tecumseth |
| New Path Youth and Family Services of Simcoe County, Barrie - Lakeshore Dr, Attendance Centre | Barrie |
| New Path Youth and Family Services of Simcoe County, Barrie Head Office, Adolescent Outreach Program | Barrie |
| New Path Youth and Family Services of Simcoe County, Barrie Head Office, Early Years Services | Barrie |
| New Path Youth and Family Services of Simcoe County, Barrie Head Office | Barrie |
| New Path Youth and Family Services of Simcoe County, Barrie Head Office, Parenting Support Programs | Barrie |
| New Path Youth and Family Services of Simcoe County, Bradford Office, Child and Youth Mental Health Quick Access Clinic | Bradford West Gwillimbury |
| New Path Youth and Family Services of Simcoe County, Bradford Office, Youth and Family Counselling Services | Bradford West Gwillimbury |
| New Path Youth and Family Services of Simcoe County, Cookstown Office, Live in Treatment Services | Innisfil |
| New Path Youth and Family Services of Simcoe County, Midland Office, Child and Youth Mental Health Quick Access Clinic | Midland |
| New Tecumseth Public Library, Alliston, Memorial Branch | New Tecumseth |
| New Tecumseth Public Library, Beeton, DA Jones Branch | New Tecumseth |
| New Tecumseth Public Library, Tottenham, Pam Kirkpatrick Branch | New Tecumseth |
| New Tecumseth Singers (The) | New Tecumseth |
| New Tecumseth. Fire Department | New Tecumseth |
| New Tecumseth. Municipal Office | New Tecumseth |
| New Tecumseth. Municipal Office, No physical address, Rest Stations for Extreme Weather Relief | New Tecumseth |
| Next Gen Men | Simcoe |
| Next Gen Men, NGM Boys+ Club | Simcoe |
| NEXT STEP, Literacy and Basic Skills | New Tecumseth |
| NEXT STEP | New Tecumseth |
| Noor-Ul-Islam of Ontario, Barrie, Barrie Mosque | Barrie |
| North Simcoe Muskoka Acquired Brain Injury Collaborative, Mailing Address | Barrie |
| North Simcoe Muskoka Home and Community Care Support Services, Barrie - Sperling Dr | Barrie |
| North Simcoe Muskoka Home and Community Care Support Services, Barrie - Sperling Dr, Telehomecare | Barrie |
| North Simcoe Muskoka Hospice Palliative Care Network | Orillia |
| North Simcoe Muskoka Hospice Palliative Care Network, Orillia, Education and consultation | Orillia |
| North Simcoe Muskoka Hospice Palliative Care Network, Orillia | Orillia |
| North Simcoe Muskoka Specialized Geriatric Services | Barrie |
| North York General Hospital, Phillips House, Child and Adolescent Eating Disorders Program | Toronto |
| Nottawasaga Cooperative Homes | New Tecumseth |
| Nottawasaga Futures, Alliston, Business Excellence Resource Centre | New Tecumseth |
| Nottawasaga Handweavers and Spinners Guild | New Tecumseth |
| Nottawasaga Valley Conservation Authority, Camp Tiffin, Tiffin Centre for Conservation | Utopia |
| Nottawasaga Valley Conservation Authority, New Lowell, New Lowell Campground & Conservation Park | Clearview (Simcoe County) |
| Nottawasaga Valley Conservation Authority, Tiffin Centre for Conservation | Utopia |
| Nottawasaga Valley Conservation Authority, Tiffin Centre for Conservation | Utopia |