| Acronym | Definition |
|---|
| PIO | Public Information Office |
| PIO | Public Information Officer |
| PIO | Press and Information Office (Cyprus) |
| PIO | Person of Indian Origin (card allows visa free entry to Indian origin people living abroad) |
| PIO | Pozycjonowanie I Optymalizacja (Polish: Positioning and Optimization) |
| PIO | Pass It On |
| PIO | Paid in Office |
| PIO | Programmed Input/Output |
| PIO | Port Installed Option (automotive) |
| PIO | Periodicals Index Online (database) |
| PIO | Public International Organization |
| PIO | Processor Input Output |
| PIO | Programmed Input Output |
| PIO | Parallel Input Output |
| PIO | Program Information Office |
| PIO | Parallel Input/Output |
| PIO | Pilot Induced Oscillations |
| PIO | Police Information Officer (various organizations) |
| PIO | Processor Input/Output |
| PIO | Peruvian Inca Orchid (hairless dog breed) |
| PIO | Primaer Immunbrist Organisationen (Sweden) |
| PIO | Police Intelligence Operations |
| PIO | Payload Integration Plan (US NASA) |
| PIO | Program Integration Office |
| PIO | Pick It Out |
| PIO | Process Information Officers |
| PIO | Personal Injury, Other (accident data) |
| PIO | Pesticide Information Office (University of Florida) |
| PIO | Pilot Involved Oscillation |
| PIO | Primary Immunodeficiency Organization |
| PIO | Project Integration Office |
| PIO | Private Input Output |
| PIO | Principal Inspecting Officers (of Railways; United Kingdom) |
| PIO | Provincial Irrigation Officer (Philippines) |
| PIO | Photographic Intelligence Officer |
| PIO | Process Improvement Opportunity (various organizations) |
| PIO | Private Industrial Operator (energy market) |
| PIO | Present Income Only |
| PIO | Provisioned/Provisioning Item Order |