| Abbreviation | Definition |
|---|---|
| PSCT | Powder Springs Community Task-force |
| PSEG | Professional Society Ethics Group |
| PSEG | Public Service Endowment Grant |
| PSFI | Pilipinas Shell Foundation, Inc. |
| PSHSA | Public Services Health and Safety Association |
| PSI | Paul Scherrer Institute |
| PSI | Philanthropic Service for Institutions |
| PSI | Poetry Slam Incorporated |
| PSI | Postpartum Support International |
| PSI | Psychological Society of Ireland |
| PSIA | Professional Ski Instructors of America |
| PSIP | Public Service Intern Program |
| PSLC | Port Shepstone Lions Club |
| PSLL | Property Owners Association of Perkins-sur-le-lac |
| PSM | PetSmart Charities |
| PSMA | Pacific Merchant Shipping Association |
| PSNI | Play Soccer Nonprofit International |
| PSO | Patient Safety Organization |
| PSRI | Poverty and Social Reform Institute |
| PSS | Pyramid Spiritual Societies |