| Eagles Nest of Waterdown, Eagles Nest Mental Health Programs and Services | Hamilton |
| Eaglesfield Community Church | Burlington |
| East Plains United Church | Burlington |
| Easter Seals Canada | Toronto Downtown North |
| Easter Seals Ontario | North York East |
| Easter Seals Ontario, West Region - Halton Region District | Burlington |
| Ebenezer Canadian Reformed Church | Burlington |
| Ebenezer United Church | Milton |
| Edgewater Senior Living | Georgetown |
| Editors Canada, Hamilton-Halton Chapter | Halton Region |
| EDS Foundation | Oakville |
| Edward's Pharmacy, Pharmacy Services | Oakville |
| EFry Hope and Help for Women, Mississauga Office | Mississauga |
| Elder Abuse Prevention Ontario | Etobicoke Central |
| ElderDog Canada, Halton Pawd - No Physical Address | Halton Region |
| Elections Canada, Wellington - Halton Hills North Electoral District, 2025 Federal Election | Halton Hills |
| Elections Canada, Burlington Electoral District, 2025 Federal Election | Burlington |
| Elections Canada, Burlington North - Milton West Electoral District, 2025 Federal Election | Milton |
| Elections Canada, Milton East - Halton Hills South Electoral District, 2025 Federal Election | Milton |
| Elections Canada, Oakville East Electoral District, 2025 Federal Election | Oakville |
| Elections Canada, Oakville West Electoral District, 2025 Federal Election | Oakville |
| Electrical Safety Authority | Cambridge |
| Elementary Teachers Federation of Ontario, Halton Local | Burlington |
| Elite Home Nursing Care, In-Home Care Services | Georgetown |
| Elizz by SE Health, Elizz Help at Home Services | Hamilton |
| eMentalHealth.ca | Ottawa |
| Emfy Health, Home Health Care Services | Mississauga |
| Emotions Anonymous, Burlington Group - No Physical Address, 12 Step Program | Burlington |
| Empowerment Council (Addiction and Mental Health), Systemic Advocacy and Education | Toronto |
| Enbridge Gas, Natural Gas Services for Halton Residents | Scarborough |
| End of Life Doula Association of Canada, End of Life Doula Association of Canada Resources and Doula Network | British Columbia |
| English Learners Club of Oakville, ESL Conversation Classes | Halton South |
| Enhanced Mobility | Oakville |
| Environment and Climate Change Canada, Hello Weather | Ottawa |
| Environment and Climate Change Canada, Meteorological Service of Canada - Weather Information | Ottawa |
| Epilepsy South Central Ontario, Mississauga | Mississauga |
| EPUC Child Care Centre, Licensed Child Care Centre | Burlington |
| Equifax Canada Inc | Toronto |
| Equilibrium, Oakville, Mood Disorder Support Group | Oakville |
| Eramosa Nonprofit Housing Corporation | Guelph-Eramosa |
| ErinoakKids, Oakville Site, Centre for Treatment and Development | Oakville |
| ErinoakKids Centre for Treatment and Development, Children's Treatment Centre (Brampton) | Brampton |
| ErinoakKids Centre for Treatment and Development, Children's Treatment Centre (Mississauga) | Mississauga |
| Ernest C Drury School for the Deaf | Milton |
| Ernest C Drury School for the Deaf, Ontario Youth Apprenticeship Program | Milton |
| Ernestine's Women's Shelter | Toronto |
| Escarpment Country Tourism Committee | Milton |
| Escudero Medical Centre | Oakville |
| Esquesing Historical Society | Georgetown |
| Estate Administration and Wills, Halton Region | Halton Region |
| Evangel Family Church | Acton |
| Evangel Pentecostal Church | Oakville |
| Exam Proctoring, Halton Region | Halton Region |
| Extendicare Burloak, Long Term Care Home | Burlington |
| Extendicare Halton Hills, Long-Term Care Centre | Halton Hills |
| Extendicare Northridge, Long Term Care Centre | Oakville |
| Extendicare West Oak Village, Long Term Care Centre | Oakville |
| EYES Child Care Burlington, Licensed Child Care Centre | Burlington |
