| P=EI | Power in Watts 
| Others |
| PEI | Passion Education Inspiration
| Others |
| PEI | Paul Ehrlich Institut
| Others |
| PEI | Peace Entered Island
| Others |
| PEI | Pereira, Colombia
| Others |
| PEI | Performance Efficiency Index
| Others |
| PEI | Performance Evaluation Interview
| Others |
| PEI | Petroleum Equipment Institute
| Others |
| PEI | Photo Electronic Imaging
| Others |
| PEI | Pix Extended Image
| Others |
| PEI | Playboy Enterprises, Inc.
| Others |
| PEI | Policy Enforcement and Implementa
| Others |
| PEI | Policy Enforcement and Implementation
| Others |
| PEI | Poly Ethylene Imine
| Others |
| PEI | PolyEtherImide
| Others |
| PEI | Porcelain and Enamel Institute
| Others |
| PEI | Porcelain Enamel Institute
| Others |
| PEI | Potato Enriched Island
| Others |
| PEI | Pre Efi Initialization
| Others |
| PEI | Primary Engine Instrumentation
| Others |
| PEI | Prince Edward Island
| Island, Province, Territory |
| PEI | Princeton Economics International
| Others |
| PEI | Princeton Environmental Institute
| Others |
| PEI | Principal End Item
| Others |
| PEI | Private Equity International
| Others |
| PEI | Progetto Educativo d'Istituto
| Others |
| PEI | Progetto Educativo d'Istituto o Piano Educativo Individualizzato
| Others |
| PEI | Program for Environmental Informatics
| Others |
| PEI | Progressive Engineering Inc
| Others |
| PEI | Prosperity Evolution Initiative
| Others |
| PEI | Proton Edar Indonesia
| Others |
| PEI | Proyecto Educativo Institucional
| Others |
| PEI | Push Effective Index
| Others |
| PEI | Push Effective Indirect
| Others |