PUI is a three letter acronym which may refer to:
- PARC User Interface, a user interface based on the WIMP (window, icon, menu, pointer) system; see PARC (company)
- IATA code for Purnea Airport, Purnea, Bihar, India
- Pokémon USA, Inc
- Pilot Under Instruction, a licensed pilot receiving instruction, as opposed to a student pilot
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