| Abbreviation | Definition |
|---|---|
| PSSI | Prague Security Studies Institute |
| PSYETA | Psychologists for Ethical Treatment of Animals |
| PSYETA | Psychologists for the Ethical Treatment of Animals |
| PTBA | Professional Trail Builders Association |
| PTD | Preserve The Dunes |
| PTFP | Public Telecommunications Funding Program |
| PTGIG | Port Townsend Gluten Intolerance Group |
| PTLDF | Pestalozzi Trust Legal Defence Fund |
| PTLL | Pittsburgh Toy Lending Library |
| PTN | Pull- Thru Network |
| PTNC | Parents as Teachers National Center |
| PTO | Parent Teacher Organisation |
| PTP | People-To-People |
| PTPD | Partnership for Technology Professional Development |
| PTPF | Piedmont Triad Partnership Foundation |
| PTPI | People To People International |
| PTS | Pali Text Society |
| PTU | Parent & Teen Universities, Inc. |
| PTU | Parent & Teen Universities, Incorporated |
| PTW | Picturing Tomorrow's World |