| | Organization Name(s) | Located In |
| | Oakdale Child and Family Services Inc | Midhurst |
 | Obi (Dr. Olisa) | Penetanguishene |
| | Office of the Federal Ombudsman for Victims of Crime | Ottawa |
 | Office of the Ombudsman of Ontario | Toronto |
 | Office of the Worker Adviser, Barrie Consultations | Barrie |
 | O'Halloran (Dr Patrick) | Midland |
| | O'Kane (Carol and Michael), Marriage Officers | Oro-Medonte |
 | Okinawa Budo Karate Dojo, Lafontaine Ryusyokai, Okinawa Goju-ryu | Lafontaine |
 | Olde Forge Community Resource Centre (The) | Ottawa |
 | On T.R.A.C. for BULLYING PREVENTION, The Raising Awareness Centre for Bullying Prevention | Midland |
 | Once Upon a Child | Barrie |
 | One Roof. North Simcoe | Midland |
 | Ontario, Ministry of Community Safety and Correctional Services, Central North Correctional Centre | Penetanguishene |
 | Ontario Aboriginal Housing Services, Rural and Native Housing Program, Barrie Portfolio | Sault Ste Marie |
 | Ontario Addiction Treatment Centres, Barrie Clinic | Barrie |
 | Ontario Blue Cross | Etobicoke |
 | Ontario Chiropractic Association | Toronto |
 | Ontario College of Pharmacists | Toronto |
 | Ontario College of Trades | Toronto |
 | Ontario Criminal Injuries Compensation Board | Toronto |
 | Ontario Early Years Centre Simcoe North-Orillia, Saturday Morning with Dad | Orillia |
 | Ontario Early Years Centre. Simcoe Grey, Alliston | Alliston |
 | Ontario Early Years Centre. Simcoe North, Emergency Baby Needs Depot. Midland | Midland |
 | Ontario Early Years Centre. Simcoe North, Grandparents Parenting Again. Midland | Midland |
 | Ontario Early Years Centre. Simcoe North, Home Child Care Provider Registry | Midland |
 | Ontario Early Years Centre. Simcoe North, Midland Centre | Midland |
 | Ontario Early Years Centre. Simcoe North, Orillia Centre | Orillia |
 | Ontario Early Years Centre. Simcoe North, Orillia Emergency Baby Needs Depot | Orillia |
 | Ontario Early Years Centre. Simcoe North, Orillia Stay and Play Program | Orillia |
 | Ontario Early Years Centre. Simcoe North, Penetanguishene Outreach Program | Penetanguishene |
 | Ontario Early Years Centre. Simcoe North, Port McNicoll Play and Learn Program | Port McNicoll |
 | Ontario Early Years Centre. Simcoe North, Saturday Morning with Dad | Midland |
| | Ontario Early Years Centre. Simcoe North, Victoria Harbour Outreach Program | Victoria Harbour |
 | Ontario Early Years Centre. Simcoe North, Washago Stay and Play Program | Orillia |
 | Ontario Early Years Centre. Simcoe North, Waubaushene Outreach Program | Waubaushene |
 | Ontario Early Years Centre. Simcoe North, Orillia, Brechin Play and Learn | Brechin |
 | Ontario Early Years Centre. Simcoe North, Orillia, Coldwater Play and Learn | Coldwater |
 | Ontario Early Years Centre. Simcoe North, Orillia, Grandparents Parenting Again | Orillia |
 | Ontario Early Years Centre. Simcoe North, Orillia, Hawkestone Hall, Hawkestone | Oro-Medonte |
 | Ontario Early Years Centre. Simcoe North, Orillia, Home Childcare Registry | Orillia |
 | Ontario Early Years Centre. Simcoe North,Orillia, Jarratt Stay and Play Program | Oro-Medonte |
| | Ontario Electronic Stewardship, Electronic Waste | Toronto |
 | Ontario Energy Board | Toronto |
 | Ontario English Catholic Teachers Association. Unit Simcoe/Muskoka | Elmvale |
 | Ontario Enhanced Driver's Licence | Toronto |
 | Ontario Federation for Cerebral Palsy | Toronto |
 | Ontario Federation of Anglers and Hunters, Invading Species Awareness Program | Peterborough (City of) |
| | Ontario Federation of Snowmobile Clubs | Barrie |
 | Ontario Federation of Snowmobile Clubs District 8, Mid Ontario Snowmobile Trails | Simcoe County |
| | Ontario Genealogical Society, Simcoe County Branch | Barrie |
| | Ontario Hooking Craft Guild, Huronia Branch | Simcoe County |
 | Ontario Human Rights Commission | Toronto |
 | Ontario Long Term Care Association | Markham |
| | Ontario Lung Association (The) | Toronto |
 | Ontario March of Dimes, Central Region, Acquired Brain Injury Services, Outreach Activity Groups in Simcoe County | Barrie |
| | Ontario March of Dimes, West Central Region - Barrie | Barrie |
| | Ontario March of Dimes, West Central Region - Barrie, Assistive Devices Program/Environmental Aids | Barrie |
| | Ontario March of Dimes, West Central Region - Barrie, DesignAbility | Barrie |
 | Ontario Medical Imaging. Midland | Midland |
 | Ontario Network for the Prevention of Elder Abuse (The), Elder Abuse Hotline | Toronto |
 | Ontario One Call | Guelph |
| | Ontario Photo Card | Ontario |
| | Ontario Poison Centre | Toronto |
 | Ontario Provincial Police, Seniors Assistance Team | Orillia |
 | Ontario Provincial Police Southern Georgian Bay, Southern Georgian Bay Detachment, Penetanguishene Satellite Office | Penetanguishene |
 | Ontario Provincial Police. Huronia West Detachment | Wasaga Beach |
 | Ontario Provincial Police. Southern Georgian Bay Detachment | Midland |
 | Ontario Provincial Police. Southern Georgian Bay Detachment, Meeting Facilities | Midland |
 | Ontario Psychological Association, Psychologists Referral Service | Toronto |
| | Ontario Registered Music Teachers Association, Barrie Branch | Barrie |
 | Ontario Retirement Communities Association | Oakville |
 | Ontario Secondary School Teachers' Federation, Simcoe County District 17 | Barrie |
 | Ontario Self Help Network (The), Barrie-Simcoe Branch | Barrie |
 | Ontario Senior Games Association. Simcoe County, District 28 | Simcoe County |
| | Ontario Seniors' Secretariat, Seniors' INFOline | Toronto |
 | Ontario Society for the Prevention of Cruelty to Animals, Midland and District, Carver Off-Leash Dog Park | Port McNicoll |
 | Ontario Society for the Prevention of Cruelty to Animals, Orillia Branch | Orillia |
 | Ontario Society for the Prevention of Cruelty to Animals. Midland and District, Domestic Shelter and Adoption Centre | Midland |
 | Ontario SPCA Marion Vernon Memorial Animal Clinic | Barrie |
 | Ontario Track 3 Ski Association for the Disabled | Etobicoke |
| | Ontario Trails Council | Deseronto |
 | Ontario Trial Lawyers Association, Trial Lawyers for Veterans | Ontario |
 | Ontario Vipassana Centre, Dhamma Torana | Egbert |
 | Ontario Women's Directorate | Midhurst |
| | Ontario Youth Apprenticeship Program, Simcoe County District School Board | Barrie |
| | Ontario Youth Apprenticeship Program, Simcoe Muskoka Catholic District School Board | Barrie |
 | Ontario. Elections Ontario, Office of The Chief Electoral Officer of Ontario | Toronto |
 | Ontario. Employment Ontario, Apprenticeship Office, Barrie Regional Office | Barrie |
 | Ontario. Legislative Offices, Leader of the Ontario Liberal Party and Premier of Ontario, Kathleen Wynne | Toronto |
 | Ontario. Legislative Offices, New Democratic Party of Ontario Leader, Andrea Horwath | Toronto |
 | Ontario. Members of the Legislative Assembly, Barrie Provincial Riding, Rod Jackson MPP | Barrie |
 | Ontario. Members of the Legislative Assembly, Kathleen Wynne Premier | Toronto |
 | Ontario. Members of the Legislative Assembly, Simcoe North Provincial Riding. Orillia Office, Garfield Dunlop MPP | Orillia |
 | Ontario. Members of the Legistlative Assembly, Simcoe North, Garfield Dunlop | Midland |
 | Ontario. Ministry of Agriculture Food and Rural Affairs. Central Region | Midhurst |
 | Ontario. Ministry of Children and Youth Services, Central East Region, Barrie Office, Special Services at Home and Assistance for Children with Severe Disabilities | Barrie |
| | Ontario. Ministry of Children and Youth Services, Ontario Child Benefit | Ontario |
 | Ontario. Ministry of Children and Youth Services, Youth Justice Services, Barrie Office | Barrie |
 | Ontario. Ministry of Children and Youth Services, Youth Justice Services, Midland Reporting Office | Midland |
 | Ontario. Ministry of Citizenship and Immigration. Central Area. Midhurst Office | Midhurst |
 | Ontario. Ministry of Community and Social Services, Custodian of Adoption Information | Toronto |
 | Ontario. Ministry of Community and Social Services, Passport Program | Barrie |
 | Ontario. Ministry of Community and Social Services. Central East Region. Barrie Office | Barrie |
 | Ontario. Ministry of Community and Social Services. Central East Region. Barrie Office, Ontario Disability Support Program, Employment Supports | Barrie |
 | Ontario. Ministry of Community and Social Services. Orillia Office, Income and Employment Supports, Employment and Training Start-Up Benefit | Orillia |
 | Ontario. Ministry of Community and Social Services. Orillia Office, Income and Employment Supports, Employment Supports | Orillia |
 | Ontario. Ministry of Community and Social Services. Orillia Office, Income and Employment Supports, Ontario Disability Support Program | Orillia |
 | Ontario. Ministry of Community Safety and Correctional Services, Adult Probation and Parole Services, Orillia | Orillia |
 | Ontario. Ministry of Community Safety and Correctional Services, Barrie Office, Probation and Parole Services | Barrie |
 | Ontario. Ministry of Community Safety and Correctional Services. Midland, Probation and Parole Services. Adult | Midland |
 | Ontario. Ministry of Community Safety and Correctional Services. Regional Supervising Coroner's Office. Central Region. Guelph Office | Guelph |
| | Ontario. Ministry of Culture, Ontario Seniors' Secretariat, Seniors' Info Online Resource | Ontario |
 | Ontario. Ministry of Education, Barrie Region, Early Learning Division, Child Care Quality Assurance and Licensing Branch | Barrie |
 | Ontario. Ministry of Education, Child Care Quality Assurance and Licensing Offices, Barrie Region | Newmarket |
| | Ontario. Ministry of Government Services, Access and Inquiry Services | Toronto |
 | Ontario. Ministry of Government Services, ServiceOntario, Central Production and Verification Services Branch | Toronto |
| | Ontario. Ministry of Government Services, ServiceOntario, Specialty Services. Change of Name | Thunder Bay |
 | Ontario. Ministry of Government Services. Office of the Registrar General | Toronto |
 | Ontario. Ministry of Health and Long-Term Care, Assistive Devices Program | Toronto |
| | Ontario. Ministry of Health and Long-Term Care, Health Care Connect | Ontario |
 | Ontario. Ministry of Health and Long-Term Care, Ontario Drug Benefit Program | Etobicoke |
 | Ontario. Ministry of Health and Long-Term Care, ServiceOntario Infoline | Toronto |
 | Ontario. Ministry of Health and Long-Term Care, Trillium Drug Program | North York |
| | Ontario. Ministry of Health and Long-Term Care, Your Health Care Options | Ontario |
 | Ontario. Ministry of Labour, District Office | Newmarket |
 | Ontario. Ministry of Labour. Downsview Office, Office of the Worker Adviser | Toronto |
 | Ontario. Ministry of Municipal Affairs and Housing, Investigation and Enforcement Unit (Maintenance and Standards Section) | Toronto |
| | Ontario. Ministry of Natural Resources, Ontario Parks, Central Region, Six Mile Lake Provincial Park | Muskoka District |
| | Ontario. Ministry of Natural Resources, Ontario Parks, Central Region, Waubaushene Beaches Provincial Nature Reserve | Tay |
 | Ontario. Ministry of Natural Resources. Ontario Parks. Central Zone, Awenda Provincial Park | Tiny |
 | Ontario. Ministry of Natural Resources. Ontario Parks. Central Zone, Springwater Provincial Park | Midhurst |
 | Ontario. Ministry of Natural Resources. Southern Region. Midhurst District Office | Midhurst |
 | Ontario. Ministry of Natural Resources. Southern Region. Midhurst District Office, Ontario Hunter Education Program | Midhurst |
 | Ontario. Ministry of Natural Resources. Southern Region. Midhurst District Office. Copeland Forest | Midhurst |
 | Ontario. Ministry of Revenue. Client Accounts and Services Branch, Guaranteed Annual Income System | Oshawa (City of) |
 | Ontario. Ministry of Revenue. Client Accounts and Services Branch, Ontario Child Care Supplement for Working Families | Oshawa (City of) |
 | Ontario. Ministry of the Attorney General, Barrie Office, Court Support | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Crown Attorney | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Enforcement and Finance, Sheriff's Office | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Family Law Information Centre | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Jury Line | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Justice of the Peace. Criminal Matters | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Ontario Court of Justice, Criminal | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Ontario Superior Court of Justice, Civil Filing Office | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Ontario Superior Court of Justice, Estates Administration | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Ontario Superior Court of Justice, Family Court | Barrie |
 | Ontario. Ministry of the Attorney General, Barrie Office, Ontario Superior Court of Justice, Small Claims Court | Barrie |
 | Ontario. Ministry of the Attorney General, Justice Ontario | Toronto |
 | Ontario. Ministry of the Attorney General, Midland Satellite Court, Ontario Court of Justice | Midland |
 | Ontario. Ministry of the Attorney General, Victims and Vulnerable Persons Division, Victim/Witness Assistance Program, Simcoe County | Barrie |
 | Ontario. Ministry of the Attorney General. Toronto, Ontario Victim Services Secretariat, Victim Support Line | Toronto |
 | Ontario. Ministry of the Environment, Barrie Office | Barrie |
 | Ontario. Ministry of the Environment, Barrie Office, Safe Drinking Water Branch | Barrie |
 | Ontario. Ministry of the Environment. North York, Spills Action Centre | North York |
 | Ontario. Ministry of Tourism, Tourism Marketing Partnership Corporation, Ontario Travel Information Centre | Barrie |
 | Ontario. Ministry of Tourism, Culture and Sport, Ontario Trillium Foundation [The] | Toronto |
 | Ontario. Ministry of Tourism, Culture and Sport. Central Area. Midhurst Office | Midhurst |
 | Ontario. Ministry of Tourism, Culture and Sports. Central Area. Midhurst Office, Ontario Sport and Recreation Communities Fund | Midhurst |
| | Ontario. Ministry of Training, Colleges and Universities, Employment Ontario Hotline | Toronto |
| | Ontario. Ministry of Training, Colleges and Universities, Labour Market Information | Ontario |
 | Ontario. Ministry of Training, Colleges and Universities, Student Financal Assistance Branch, Ontario Student Assistance Program | Thunder Bay |
 | Ontario. Ministry of Transportation, Central Region, International Registration | Barrie |
 | Ontario. Ministry of Transportation, Senior Driver Renewal Program, Senior Driver Group Education Sessions | Barrie |
 | Ontario. Ministry of Transportation. Central Region, Adopt-A-Highway Program | Toronto |
 | Ontario. Ministry of Transportation. Customer Service Office, Road Conditions/Construction Information Service | St Catharines |
 | Ontario. Seniors' Secretariat, Midhurst | Midhurst |
 | Ontario. ServiceOntario, Barrie - 34 Simcoe St Service Counter | Barrie |
 | Ontario. ServiceOntario, Land Registry Office 51 | Barrie |
 | Operation Christmas Child Shoe Box Gift Program, Barrie Area | Barrie |
| | Operation Christmas Child. Wasaga Beach | Wasaga Beach |
| | OPP Chorus | Barrie |
| | Optimum Nannies and Homecare Inc | Vancouver |
 | Order of The Eastern Star. Chapter # 240. Midland | Midland |
| | Organic Fruits and Vegetables | Penetanguishene |
| | Orillia Canada Day | Orillia |
 | Orillia Farmers Market | Orillia |
 | Orillia Fertility Associates | Orillia |
 | Orillia Housing Resource Centre | Orillia |
 | Orillia Pregnancy Resource Centre | Orillia |
 | Orillia Public Library | Orillia |
 | Orillia Soldiers Memorial Hospital, Children's Therapy Services. Occupational Therapy, Physiotherapy and Social Work Midland | Midland |
 | Orillia Soldiers' Memorial Hospital, Regional Sexual and Domestic Assault Treatment Centre, Domestic Assault Program | Orillia |
 | Orillia Winter Carnival | Orillia |
 | Orr Lake Golf Club | Elmvale |
 | Orr Lake Ratepayers Association | Springwater |
 | Osteoporosis Canada | Toronto |
| | Osteoporosis Canada, Ontario Osteoporosis Strategy, Simcoe Muskoka | Stayner |
 | Our Lady of Lourdes Catholic School. Elmvale | Elmvale |
 | Our Lady of Lourdes Roman Catholic Church. Elmvale | Elmvale |
 | Our Town Food Bank, Tottenham | Tottenham |
 | Out of the Cold - Midland | Midland |
| | Outreach Services | Barrie |
 | Ovarian Cancer Canada | Toronto |
 | Over Thirty Hockey League. Midland | Midland |
 | Overeaters Anonymous. Midland | Midland |
 | Oxfam Canada, Ontario Region | Toronto |