| PIER | Peer to Peer Information Exchange and Retrieval 
| Others |
| PIER | Penn Institute for Economic Research
| Others |
| PIER | Pensionable and Insurable Earnings Review
| Others |
| PIER | People Invested in Eternal Riches
| Others |
| PIER | Physicians Information and Education Resource
| Others |
| PIER | Portland Identification and Early Referral
| Others |
| PIER | Professionalism Integrity Excellence Relationships
| Others |
| PIER | Programs in International Educational Resources
| Others |
| PIER | Progress in Electromagnetics Research
| Others |
| PIER | Protection Involvement Education and Restoration
| Others |
| PIER | Public Information Education Relations
| Others |
| PIER | Public Interest Energy Research
| Others |