| IAVGO Community Legal Clinic | Toronto |
| Ideal Chiropractic | Barrie |
| Ideal Rebekah Lodge 199 | Midland |
| Iglesia Pentecostal LaSenda, Barrie | Barrie |
| Imani's Place Foundation | New Tecumseth |
| Immaculate Conception Roman Catholic Church, Alliston | New Tecumseth |
| In Support Of Children Counselling, Unpublished, Counselling Services | Collingwood |
| 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, Accessibility, Resources and Connections | Barrie |
| Independent Living Services Simcoe County, Assisted Living Services for Seniors | Barrie |
| Independent Living Services Simcoe County, Barrie, Community Development and Training and Consultation | Barrie |
| Independent Living Services Simcoe County, Barrie, Homemaking Program | 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 |
| Indigenous Diabetes Health Circle, Central Region, Indigenous Diabetes Health Circle Central Region | Barrie |
| Information and Privacy Commissioner of Ontario | Toronto Downtown |
| Information Orillia, Orillia Public Library, Income Tax Clinic | Orillia |
| Information Orillia, Orillia Public Library | Orillia |
| Information Orillia, Orillia Public Library, Orillia Volunteer Centre | Orillia |
| Inner Growth Counselling & Psychotherapy | Barrie |
| Innisfil Community Church | Innisfil |
| Innisfil Community Church, Innisfil Food Bank | Innisfil |
| Innisfil Hearing Centre, Angus, Denture and Hearing Clinic, Angus | Essa |
| Innisfil Hearing Centre, Innisfil | 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 |
| Inniswood Baptist Church | Barrie |
| Insurance Bureau of Canada, Ontario Head Office, Consumer Information Centre | Toronto |
| Integrated Autism Consulting, Barrie | Barrie |
| Intelligent Elders Club (The) | Orillia |
| International Brotherhood of Electrical Workers, Barrie Office, Local 353 | Barrie |
| International Pen Friends | Orillia |
| International Schools for Bright and Gifted Children, King's College School | Caledon East |
| IOOF Seniors Homes, Barrie - 10 Brooks St, Odd Fellow and Rebekah Home | Barrie |
| IOOF Seniors Homes, Barrie - 20 Brooks St, Heritage Place | Barrie |
| Irish Claddagh Club of Barrie and District | Barrie |
| Itosu Kai Karate Collingwood | Collingwood |