| Abbreviation | Definition |
|---|---|
| PHF | Project Homefront Fund |
| PHF | Public Health Foundation |
| PHH | Project Harvest Hope |
| PHOFFoundation | Philanthropists Helping Our Future |
| PHR | Physicians for Human Rights |
| PhRMA | Pharmaceutical Research and Manufacturers of America |
| PHS | Pennsylvania Horticultural Society |
| PHS | Pontiac Historic Services |
| PHS | Presbyterian Healthcare Services |
| PHUR | Pets Helping Us Recover |
| PHW | Partnership to Health through Water |
| PHWT | Physically Handicapped Welfare Trust |
| PI | Population Institute |
| PI | Project Inform |
| PIA | Parachuting Industry Association |
| PIAC | Public Interest Advocacy Centre (Australia Canada) |
| PIAC | Public Interest Advocacy Centre (Australia & Canada) |
| PIAC | Public Interest Advocacy Centre, The |
| PIAS | Presque Isle Audubon Society |
| PIC | Pinchot Institute for Conservation |