PPI
- Gabarit passe-partout international
- Intel 8255
- Italian People's Party (1919)
- Italian People's Party (1994)
- PPI Holdings, Inc.
- Pakistan Press International
- Parallel Peripheral Interface
- Pareto priority index
- Patient and public involvement
- Payment protection insurance
- Peace Party of India
- Perusahaan Perdagangan Indonesia
- Philips Phonographische Industries
- Phonographic Performance Ireland
- Pirate Parties International
- Pixels per inch
- Plan position indicator
- Polly Peck International
- Polymethylene polyphenylene isocyanate
- Polyproline I helix
- Port Pirie Airport
- Positive polarity item
- Prepulse inhibition
- Primarily Primates
- Producer price index
- Programmable Peripheral Interconnect
- Progressive Policy Institute
- Protein–protein interaction
- Proton-pump inhibitor
- Psychopathic Personality Inventory
- Psychophysiological Interaction
- Pulse Polio
- Stepstone