| Above and Beyond | Peterborough |
| Aces of Harmony Chorus | Peterborough |
| Achilles Canada, No Physical Location, Peterborough Chapter | Selwyn Township |
| Active Living Physiotherapy and Fitness Club | Peterborough |
| Activity Haven Senior Centre | Peterborough |
| Addiction Centre Toronto, ACT Peterborough | Peterborough |
| Agilec, Peterborough, Agilec - Integrated Employment Services | Peterborough |
| Al-Anon Family Groups, Peterborough - No physical address, Al-Anon / Alateen Family Groups - Peterborough | Peterborough |
| Alcoholics Anonymous, Peterborough, Kawartha District 86 | Peterborough |
| Alexander Respiratory Diagnostic Services | Peterborough |
| Align Home Health Care, Peterborough | Peterborough |
| Alz Well That Enz Well, Inc., Alz Well That Enz Well | Alnwick/Haldimand |
| Alzheimer Society, Peterborough Office, Peterborough, Kawartha Lakes, Northumberland and Haliburton | Peterborough |
| Angels of Flight Canada | Peterborough |
| AON Inc., Peterborough - Clonsilla Avenue, Royal Gardens Retirement Residence | Peterborough |
| AON Inc., Peterborough - 131 Charlotte Street, Empress Gardens Retirement Residence | Peterborough |
| AON Inc., Peterborough - Sherbrooke Street, Canterbury Gardens Retirement Residence | Peterborough |
| AON Inc., Peterborough - 100 Charlotte Street, Princess Gardens Retirement Residence | Peterborough |
| AON Inc., Millbrook - Centennial Lane, Centennial Place Long Term Care Home | Millbrook |
| AON Inc., Peterborough - 131 Charlotte Street, Rehabilitation Package | Peterborough |
| AON Inc., Peterborough - Sherbrooke Street, Canterbury Gardens Garden Home Bungalows | Peterborough |
| AON Inc., Royal Gardens - Garden Home Bungalows | Peterborough |
| AOTS Community Homes Inc | Peterborough |
| Applewood Retirement Residence | Peterborough |
| Art Gallery of Peterborough | Peterborough |
| Art School of Peterborough | Peterborough |
| Arthritis Society Canada, Central East Region - Peterborough | Peterborough |
| Asphodel Norwood Ministerial Association Food Bank | Norwood |
| Assaulted Women's Helpline | Toronto |
| Auburn Retirement Village of Peterborough, Inc. | Peterborough |
| Autism Home Base | Bowmanville |
