| IAVGO Community Legal Clinic | Toronto |
| Images Thanksgiving Studio Tour | Simcoe County |
| Imani's Place Foundation | New Tecumseth |
| Immaculate Conception Roman Catholic Church, Alliston | New Tecumseth |
| Inclusive Milestones Child Development Centres, Clinical Services | Barrie |
| Inclusive Milestones Child Development Centres, Educational Services | Barrie |
| Inclusive Milestones Child Development Centres, Recreation Services | Barrie |
| Income Security Advocacy Centre | Toronto |
| Independent Electricity System Operator, Mailing Address, saveONenergy Program | Barrie |
| Independent Living Services Simcoe County | Barrie |
| Independent Living Services Simcoe County, Assistive Technology & Aging at Home | Barrie |
| Independent Living Services Simcoe County, Barrie | Barrie |
| Independent Living Services Simcoe County, Personal Support Services | Barrie |
| Independent Living Services Simcoe County, Online / Web Service, Quipit | Barrie |
| Information and Privacy Commissioner of Ontario | Toronto Downtown |
| Information Orillia, Orillia Public Library | Orillia |
| Innisfil Community Church | Innisfil |
| Innisfil Community Church, Innisfil Food Bank | Innisfil |
| Innisfil Historical Society | Innisfil |
| Innisfil ideaLAB & Library, Cookstown Branch | Innisfil |
| Innisfil ideaLAB & Library, Lakeshore Branch | Innisfil |
| Innisfil ideaLAB & Library, Stroud Branch | Innisfil |
| Innisfil Taxi | Innisfil |
| Innisfil. Fire and Rescue Service | Innisfil |
| Insurance Bureau of Canada, Ontario Head Office, Consumer Information Centre | Toronto |
| Integrated Autism Consulting, Barrie | Barrie |
| International Schools for Bright and Gifted Children, King's College School | Caledon East |
| IS2 Workforce Solutions, Barrie | Barrie |