| Oak City Pharmacy, Pharmacy Services | Oakville |
| Oak Lake Medical Centre | Oakville |
| Oak Lake Pharmacy, Pharmacy Services | Oakville |
| Oak Park Community Pharmacy, Pharmacy Services | Oakville |
| Oak Park Family Care Centre, Family Practice and Walk-in Clinic | Oakville |
| Oak Park Medical Clinic | Oakville |
| Oak Park Neighbourhood Centre, Oakville - Sawgrass Dr | Oakville |
| Oak Park Neighbourhood Centre, Food Bank | Oakville |
| Oak Park Neighbourhood Centre, Low Income Supports | Oakville |
| Oak Park Neighbourhood Centre, Churchill Neighbourhood Centre | Oakville |
| Oak Park Neighbourhood Centre, Youth & Adult Programs | Oakville |
| Oak Park Neighbourhood Centre, Year Round Low Income Tax Clinic | Oakville |
| OakMed Family Health Team | Oakville |
| Oakridge Bible Chapel | Oakville |
| Oak-Trafalgar Medical Clinic, Family Practice and Walk-in Clinic | Oakville |
| Oakvillage Pharmacy, Pharmacy Services | Oakville |
| Oakville & District Kennel Club | Oakville |
| Oakville (Milton) Model Flying Club | Milton |
| Oakville Art Society | Oakville |
| Oakville Arts Council | Oakville |
| Oakville Association of Knitters and Crocheters | Oakville |
| Oakville Cardiologists, Dorval site | Oakville |
| Oakville Cardiologists, North site | Oakville |
| Oakville Centre for the Performing Arts | Oakville |
| Oakville Centre for the Performing Arts, Volunteer Group | Oakville |
| Oakville Chamber Orchestra | Oakville |
| Oakville Chinese Network Society, Cultural Heritage Group | Oakville |
| Oakville Choir for Children & Youth | Oakville |
| Oakville Choral | Oakville |
| Oakville Christian Centre | Oakville |
| Oakville Club (The) | Oakville |
| Oakville Cricket Club | Oakville |
| Oakville Curling Club | Oakville |
| Oakville Cycling Club | Oakville |
| Oakville Endoscopy Centre | Oakville |
| Oakville Festivals of Film and Art | Oakville |
| Oakville Galleries, Centennial Square | Oakville |
| Oakville Galleries, Gairloch Gardens | Oakville |
| Oakville Gamers | Oakville |
| Oakville Health Centre Clinic, Family Practice and Walk-in Clinic | Oakville |
| Oakville Historical Society | Oakville |
| Oakville Historical Society, Merrick Thomas Farm House Museum | Oakville |
| Oakville Horticultural Society | Oakville |
| Oakville Improv Theatre Company | Oakville |
| Oakville Lawn Bowling Club | Oakville |
| Oakville Literary Cafe (The) | Oakville |
| Oakville Masters Men's Slo-Pitch League | Oakville |
| Oakville Masters Swim Club | Oakville |
| Oakville Meals on Wheels | Oakville |
| Oakville Museum At Erchless Estate | Oakville |
| Oakville Newcomers' Club | Oakville |
| Oakville Pentecostal Apostolic Church | Oakville |
| Oakville Pharmacy, Pharmacy Services | Oakville |
| Oakville Physiotherapy Centre | Oakville |
| Oakville Players | Oakville |
| Oakville Power Boat Club | Oakville |
| Oakville Public Library, Central Branch, Branch Specific Services | Oakville |
| Oakville Public Library, Accessible Collections & Services | Oakville |
| Oakville Public Library, Central Branch, Community Food Corner | Oakville |
| Oakville Public Library, Clearview Branch, Branch Specific Services | Oakville |
| Oakville Public Library, Clearview Branch, Community Food Corner | Oakville |
| Oakville Public Library, Glen Abbey Branch, Branch Specific Services | Oakville |
| Oakville Public Library, Glen Abbey Branch, Community Food Corner | Oakville |
| Oakville Public Library, Iroquois Ridge Branch, Branch Specific Services | Oakville |
| Oakville Public Library, Library Services | Oakville |
| Oakville Public Library, OPL Express | Oakville |
| Oakville Public Library, Newcomer Programs | Oakville |
| Oakville Public Library, Sixteen Mile Branch, Branch Specific Services | Oakville |
| Oakville Public Library, White Oaks Branch, Branch Specific Services | Oakville |
| Oakville Public Library, Woodside Branch, Branch Specific Services | Oakville |
| Oakville Quilters' Guild | Oakville |
| Oakville React | Oakville |
| Oakville Scottish Country Dance Group | Oakville |
| Oakville SDA Church | Oakville |
| Oakville Senior Citizens Residence | Oakville |
| Oakville Senior Ladies Basketball League | Oakville |
| Oakville Sewers Forum | Oakville |
| Oakville Soccer Club | Oakville |
| Oakville Speed Skating Club | Oakville |
| Oakville Strokers | Oakville |
| Oakville Symphony | Oakville |
| Oakville Town Medical Clinic, Walk-in Clinic and Family Practice | Oakville |
| Oakville Trafalgar Badminton Club, Recreational Badminton | Oakville |
| Oakville Vocal Arts Festival | Oakville |
| Oakville Wind Orchestra | Oakville |
| Oakville Yacht Squadron | Oakville |
| Oakville Yacht Squadron, Sailing School | Oakville |
| Oakville. Building, Planning and Development, Heritage Oakville Advisory Committee | Oakville |
| Oakville. Finance Department, Seniors Property Tax Rebate / Deferral | Oakville |
| Oakville. Fire Department, Fire Services | Oakville |
| Oakville. Municipal Enforcement Services, Parking Operations | Oakville |
| Oakville. Parks and Open Space, Lions Valley Park | Oakville |
| Oakville. Parks and Open Space, Leash Free Dog Parks | Oakville |
| Oakville. Parks and Open Space, Outdoor Skating Rinks | Oakville |
| Oakville. Parks and Open Space, Parks & Gardens | Oakville |
| Oakville. Parks and Open Space, Trail System | Oakville |
| Oakville. Parks and Open Space, Oakville Harbours | Oakville |
| Oakville. Parks and Open Space, Greenhouse/Conservatory Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Aquatics Programs | Oakville |
| Oakville. Recreation and Culture, Glen Abbey Community Centre, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Indoor and Outdoor Swimming Pools | Oakville |
| Oakville. Recreation and Culture, Iroquois Ridge Community Centre, Iroquois Ridge Older Adults Centre | Oakville |
| Oakville. Recreation and Culture, Iroquois Ridge Community Centre, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Joshua's Creek Arenas, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Kinoak Arena, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Maple Grove Arena, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Oakville Recreational Leagues | Oakville |
| Oakville. Recreation and Culture, Santa Claus Parade | Oakville |
| Oakville. Recreation and Culture, Oakville Trafalgar Community Centre, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Public Skating | Oakville |
| Oakville. Recreation and Culture, Queen Elizabeth Park Community and Cultural Centre, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Queen Elizabeth Park Older Adult Centre | Oakville |
| Oakville. Recreation and Culture, River Oaks Community Centre, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, River Oaks Community Centre, River Oaks Mature Adults Club | Oakville |
| Oakville. Recreation and Culture, Seniors Programs | Oakville |
| Oakville. Recreation and Culture, Sir John Colborne Recreation Centre for Seniors, Interlink Choir | Oakville |
| Oakville. Recreation and Culture, Sir John Colborne Recreation Centre for Seniors, Seniors Working Action Group | Oakville |
| Oakville. Recreation and Culture, Sir John Colborne Recreation Centre for Seniors | Oakville |
| Oakville. Recreation and Culture, Sixteen Mile Sports Complex, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Trafalgar Park Community Centre, Recreation Facilities & Programs | Oakville |
| Oakville. Recreation and Culture, Trafalgar Park Older Adults Centre, Kerr Street Singers | Oakville |
| Oakville. Recreation and Culture, Trafalgar Park Older Adults Centre | Oakville |
| Oakville. ServiceOakville, Municipal Services | Oakville |
| Oakville. ServiceOakville, Driveway Snow Windrow Clearing Program | Oakville |
| Oakville. ServiceOakville, Property Tax Payments | Oakville |
| Oakville. Town Council | Oakville |
| Oakville. Town Council, Mayor - Rob Burton | Oakville |
| Oakville. Town Council, Ward 1 Town and Regional Councillor - Sean O'Meara | Oakville |
| Oakville. Town Council, Ward 1 Town Councillor - Jonathan McNeice | Oakville |
| Oakville. Town Council, Ward 2 Town and Regional Councillor - Cathy Duddeck | Oakville |
| Oakville. Town Council, Ward 2 Town Councillor - Ray Chisholm | Oakville |
| Oakville. Town Council, Ward 3 Town and Regional Councillor - Janet Haslett-Theall | Oakville |
| Oakville. Town Council, Ward 3 Town Councillor - Dave Gittings | Oakville |
| Oakville. Town Council, Ward 4 Town and Regional Councillor - Allan Elgar | Oakville |
| Oakville. Town Council, Ward 4 Town Councillor - Peter Longo | Oakville |
| Oakville. Town Council, Ward 5 Town and Regional Councillor - Jeff Knoll | Oakville |
| Oakville. Town Council, Ward 5 Town Councillor - Marc Grant | Oakville |
| Oakville. Town Council, Ward 6 Town and Regional Councillor - Tom Adams | Oakville |
| Oakville. Town Council, Ward 6 Town Councillor - Natalia Lishchyna | Oakville |
| Oakville. Town Council, Ward 7 Town and Regional Councillor - Nav Nanda | Oakville |
| Oakville. Town Council, Ward 7 Town Councillor - Scott Xie | Oakville |
| Oakville. Transit | Oakville |
| Oakville. Transit, care-A-van | Oakville |
| Oasis Centre des femmes, Oasis Centre des Femmes, Brampton Satellite Office | Brampton |
| Older Women's Network | Toronto |
| Omagh Church of Christ, Milton | Milton |
| OmbudService for Life and Health Insurance, Online Services | Toronto |
| Ombudsman for Banking Services and Investments, Toronto | Toronto |
| Ombudsman Ontario | Toronto |
| Ontario Society of Chiropodists, Newmarket | Newmarket |
| One Health Medical Center, Oakville, Family Practice and Walk-in Clinic | Oakville |
| One Vascular Imaging, Oakville | Oakville |
| Ontario Addiction Treatment Centres, Methadone Maintenance Treatment | Oakville |
| Ontario Ancestors, Halton Peel Branch - Mailing Address, Genealogy Services | Halton Region |
| Ontario Association of the Deaf | North York |
| Ontario Caregiver Organization | Toronto |
| Ontario College of Pharmacists | Toronto Downtown North |
| Ontario Dental Association | Toronto Downtown North |
| Ontario Diagnostic Centres, Oakville, Diagnostic Imaging | Oakville |
| Ontario Diagnostic Centres, Milton, Diagnostic Imaging | Milton |
| Ontario Electric Railway Historical Association, Streetcar Museum | Milton |
| Ontario Energy Board, Consumer Information and Protection | Toronto |
| Ontario Energy Board, Ontario Electricity Support Program | Toronto |
| Ontario Federation of Agriculture, Guardian Network (The) - Suicide Prevention Program | Ontario |
| Ontario Health atHome, Etobicoke | Etobicoke Central |
| Ontario Health atHome, Burlington Office | Burlington |
| Ontario Health atHome, Burlington - Fairview St, Acclaim Health Community Nursing Clinic | Burlington |
| Ontario Health atHome, Georgetown, Paramed-Georgetown Community Nursing Clinic | Georgetown |
| Ontario Health atHome, Milton - Main St E, Acclaim Health Community Nursing Clinic | Milton |
| Ontario Health atHome, Milton Office | Milton |
| Ontario Health atHome, Mississauga Office | Mississauga |
| Ontario Health atHome, Regional Learning Centre | Oakville |
| Ontario Health atHome, Oakville - Speers Rd, Acclaim Health Community Nursing Clinic | Oakville |
| Ontario Medical Imaging, Georgetown, Diagnostic Imaging | Georgetown |
| Ontario Medical Supply | Mississauga |
| Ontario Ministry of Municipal Affairs and Housing, Landlord and Tenant Board Southern Office, Ontario Landlord and Tenant Board | Hamilton |
| Ontario Poison Centre | Toronto Downtown Central |
| Ontario Provincial Police, Burlington Detachment, Highway Safety Division | Burlington |
| Ontario Psychological Association, Psychologists Referral Service | Toronto |
| Ontario Senior Games Association, Halton District 21 | Milton |
| Ontario Society of Registered Psychotherapists | Toronto Downtown Central |
| Ontario Society of Senior Citizens' Organizations | Toronto |
| Ontario Steam and Antique Preservers Association | Milton |
| Ontario. Elections Ontario, Toronto | Toronto |
| Ontario. Members of Provincial Parliament, Burlington Riding, Provincial Constituency Office – Natalie Pierre | Burlington |
| Ontario. Members of Provincial Parliament, Milton Riding, Provincial Constituency Office - Zee Hamid | Milton |
| Ontario. Members of Provincial Parliament, Oakville North-Burlington Riding, Provincial Constituency Office - Effie Triantafilopoulos | Oakville |
| Ontario. Members of Provincial Parliament, Oakville Riding, Provincial Constituency Office - Stephen Crawford | Oakville |
| Ontario. Members of Provincial Parliament, Wellington-Halton Hills Riding, Provincial Constituency Office - Joseph Racinsky | Centre Wellington |
| Ontario. Ministry for Seniors and Accessibility | Toronto |
| Ontario. Ministry of Children, Community and Social Services, Burlington - Itabashi Way, Ontario Disability Support Program | Burlington |
| Ontario. Ministry of Children, Community and Social Services. Support Services for Male Survivors of Sexual Abuse Program | Toronto |
| Ontario. Ministry of Finance, Oshawa, Guaranteed Annual Income System | Oshawa |
| Ontario. Ministry of Health, Public Health Care | Toronto Downtown Central |
| Ontario. Ministry of Health, Trillium Drug Program | Etobicoke |
| Ontario. Ministry of Health, Health Care Connect | Toronto Downtown Central |
| Ontario. Ministry of Health, Health811 | Toronto Downtown Central |
| Ontario. Ministry of Health, MedsCheck | Toronto Downtown Central |
| Ontario. Ministry of Health, Refugee HealthLine | Toronto Downtown Central |
| Ontario. Ministry of Health, Smoking Cessation Program | Toronto Downtown Central |
| Ontario. Ministry of Health, Assistive Devices Program | North York Central |
| Ontario. Ministry of Health, Home Oxygen Therapy | North York Central |
| Ontario. Ministry of Health, Ontario Public Drug Programs | Etobicoke |
| Ontario. Ministry of Health, Ontario Health Insurance Plan | Toronto Downtown Central |
| Ontario. Ministry of Health, Dental Care For Low-Income Seniors | Toronto |
| Ontario. Ministry of Health, Medical assistance in dying and end-of-life decisions | Toronto Downtown Central |
| Ontario. Ministry of Labour, Immigration, Training and Skills Development, e-Channel | Toronto |
| Ontario. Ministry of Long-Term Care, Long-Term Care Family Support and Action Line | Toronto Downtown Central |
| Ontario. Ministry of Long-Term Care, Online service, Find a long-term care home in Ontario | Ontario |
| Ontario. Ministry of Long-Term Care, Reports on Long-Term Care Homes | Toronto Downtown Central |
| Ontario. Ministry of Public and Business Service Delivery and Procurement. Insurance and Claims Services Branch, Motor Vehicle Accident Claims Fund | Toronto |
| Ontario. Ministry of the Attorney General, Milton Courthouse, Ontario Court of Justice - Criminal Court | Milton |
| Ontario. Ministry of the Attorney General, Burlington, Ontario Court of Justice - Criminal Court | Burlington |
| Ontario. Ministry of the Attorney General, Burlington, Ontario Court of Justice - Criminal Youth Court | Burlington |
| Ontario. Ministry of the Attorney General, Burlington, Superior Court of Justice - Small Claims Court | Burlington |
| Ontario. Ministry of the Attorney General, Milton Courthouse, Ontario Court of Justice - Criminal Youth Court | Milton |
| Ontario. Ministry of the Attorney General, Milton Courthouse, Ontario Court of Justice - Family Court | Milton |
| Ontario. Ministry of the Attorney General, Milton Courthouse, Superior Court of Justice - Civil Court | Milton |
| Ontario. Ministry of the Attorney General, Milton Courthouse, Superior Court of Justice - Criminal Court | Milton |
| Ontario. Ministry of the Attorney General, Milton Courthouse, Superior Court of Justice - Family Court | Milton |
| Ontario. Ministry of the Attorney General, Milton Courthouse, Superior Court of Justice - Small Claims Court | Milton |
| Ontario. Ministry of the Attorney General, Hamilton Services, Office of the Public Guardian and Trustee (OPGT) - Guardianship Investigations | Hamilton |
| Ontario. Ministry of the Attorney General, Hamilton Services, Office of the Public Guardian and Trustee | Hamilton |
| Ontario. Ministry of the Attorney General. Office of the Public Guardian and Trustee | Toronto |
| Ontario. Ministry of the Environment, Conservation and Parks, Bronte Creek Provincial Park | Oakville |
| Ontario. Ministry of the Environment, Conservation and Parks, Ontario Parks | Peterborough |
| Ontario. Ministry of the Environment, Conservation and Parks, Public Information Centre | Toronto |
| Ontario. Ministry of the Solicitor General, Animal Abuse Hotline | Toronto |
| Ontario. Ministry of Tourism, Culture and Sport, Ontario Travel Information Centre - Toronto | Toronto |
| Ontario. Ministry of Transportation, Senior Driver Renewal Program | Halton Region |
| Ontario. Ministry of Transportation, Traveller's Information | Ontario |
| Ontario. Premier (Doug Ford), Toronto | Toronto |
| Optician On Wheels, Mobile optometrist | Etobicoke Central |
| Optimal Health Pharmacy, Burlington, Pharmacy Services | Burlington |
| Origins Pharmacy, Milton, Pharmacy Services | Milton |
| Origins Pharmacy and Compounding Lab, Oakville - 3075 Hospital Gate, Pharmacy Services | Oakville |
| Origins Pharmacy and Home Health Care Centre, Pharmacy Services | Oakville |
| Osteoporosis Canada | North York East |
| Ostomy Canada Society, Halton/Peel Peer Support Group | Oakville |
| Ovarian Cancer Canada | North York Central |
| Overeaters Anonymous, Oakville / Burlington Area Meetings | Burlington |
