| Rapid Addiction Treatment Centre, Medical Treatment and Counselling for Addictions | Clarkson |
| Ray Pharmacy, Pharmacy Services | Oakville |
| Rebecca Medical Walk In Clinic, Walk-in Medical Clinic | Oakville |
| Redhill Church | Milton |
| Redleaf Cultural Integration, Burlington Chinese Community Connection | Burlington |
| Region of Halton Dart League | Georgetown |
| Rehoboth Canadian Reformed Church of Burlington-Waterdown | Burlington |
| Re-Imagine Ontario, Oakville, Community Support Services for Children, Youth and Seniors | Oakville |
| Remedy's Rx Aldershot Village Pharmacy, Pharmacy Services | Burlington |
| Remedy's Rx Progressive Pharmacy, Pharmacy Services | Burlington |
| Remedy'sRx Pharmacy, Oakville - Lakeshore Rd E (Madill Health-Aid Pharmacy), Pharmacy Services | Oakville |
| Remembrance Day Ceremonies, Burlington | Burlington |
| Renascent, Wright Centre | Toronto |
| Retired Teachers of Ontario, Halton District 15 - No Physical Address | Halton Region |
| Retired Women Teachers of Ontario, No Physical Address, Lydia Snow North Halton Branch | Halton North |
| Retirement Homes Regulatory Authority | Toronto Downtown Central |
| Retirement Homes Regulatory Authority, Online service, Find a retirement home in Ontario | Ontario |
| Retreads Motorcycle Club International, Ontario South Chapter - Mailing Address, Social Club for Motorcyclists and Enthusiasts | Halton Region |
| Rexall Pharma Plus, Burlington - Brant St, Pharmacy Services | Burlington |
| Rexall Pharma Plus, Burlington - Guelph Line, Pharmacy Services | Burlington |
| Rexall Pharma Plus, Burlington - New St, Pharmacy Services | Burlington |
| Rexall Pharmacy, Acton - Queen St E, Pharmacy Services | Halton Hills |
| Rexall Pharmacy, Milton - Derry Rd W, Pharmacy Services | Milton |
| Rexall Pharmacy, Oakville - Lakeshore Rd W, Pharmacy Services | Oakville |
| Rexall Pharmacy, Oakville - Maple Grove Rd, Pharmacy Services | Oakville |
| Richard III Society of Canada | Burlington |
| Right at Home Canada, Burlington-Milton, In Home Care Services | Burlington |
| Right at Home Canada, Oakville, In Home Care Services | Oakville |
| River Glen Pharmacy, Pharmacy Services | Oakville |
| River Oaks Community Church | Oakville |
| River Oaks Medical Pharmacy, Pharmacy Services | Oakville |
| ROCK, Burlington ROCK Hub - Burloak, Our Community Cares - Food Pantry | Burlington |
| ROCK, Burlington ROCK Hub - Warwick, Our Community Cares - Food Pantry | Burlington |
| Roedean Cooperative Homes, John Scott Building | Oakville |
| Rogers Connected for Success | Toronto |
| Routes Adventures | Kingston |
| Royal Botanical Gardens | Burlington |
| Royal Botanical Gardens, Volunteer Program | Burlington |
| Royal Canadian Legion, Acton - Branch 197 | Acton |
| Royal Canadian Legion, Georgetown - Branch 120 | Georgetown |
| Royal Canadian Legion, Burlington - Branch 60 | Burlington |
| Royal Canadian Legion, Milton - Branch 136 | Milton |
| Royal Canadian Legion, Oakville - Branch 114 | Oakville |
| Royal Canadian Legion, Oakville - Bronte Branch 486 | Oakville |
| Royal Canadian Legion, Acton - Branch 197, Ladies Auxiliary | Acton |
| Royal Canadian Legion, Burlington - Branch 60, Ladies Auxiliary | Burlington |
| Royal Canadian Legion Branch 120, Georgetown - Branch 120, Ladies Auxiliary | Georgetown |
| Royal Canadian Naval Benevolent Fund | Ottawa |
| Royal Scottish Country Dance Society, Burlington (Ontario) Branch - Mailing Address | Burlington |
| Rural Ottawa South Support Services, Telephone Service for Seniors (55+), A Friendly Voice | Ottawa |
