| Painswick Garden Club | Barrie |
| Pal Counselling & Associates, Barrie | Barrie |
| Parents Against Racism Simcoe County, Black Fathers Alliance | Barrie |
| Parents Against Racism Simcoe County, Mental Health Support | Barrie |
| Parents Against Racism Simcoe County, Parent Support Group | Barrie |
| Parents Against Racism Simcoe County | Barrie |
| Parents Against Racism Simcoe County, Tutoring Support | Barrie |
| Parents for Children's Mental Health, Simcoe County Chapter | |
| Parkinson Canada, Support Groups | Barrie |
| Passport Health, Barrie, Barrie Travel Clinic | Barrie |
| Patient / Client and Family Council, Penetanguishene | Penetanguishene |
| PFLAG Canada, No Physical Location, Barrie-Simcoe Chapter | Barrie |
| Pick-L's Nursing Footcare, Mobile Service | Bradford West Gwillimbury |
| Pilipinong Migrante sa Barrie | Barrie |
| Plan International Canada | Toronto |
| Playsmart Centre, Georgian Downs | Innisfil |
| PLC Sports Management, PLC Sports Men's Hockey League | Innisfil |
| POK Global Care | Brampton |
| Polish Alliance, Barrie | Springwater |
| Pregnancy and Infant Loss (PAIL) Network | |
| Prevention of Senior Abuse Network Simcoe County, Barrie - No Physical Address | Barrie |
| Procyon Wildlife Rehabilitation and Education Centre, Procyon Wildlife | Beeton |
| Professional Footcare, Barrie | Barrie |
| Project Lifesaver Simcoe | Barrie |
| Prom Glitz, Barrie | Barrie |
| Prosper Canada, Toronto | Toronto |
| Public Health Ontario, Orillia Office, Public Health Ontario, Orillia Office | Orillia |