LPI may refer to:
- Places
- Linköping SAAB Airport, Sweden (IATA code)
- Linus Pauling Institute at Oregon State University
- La Pyramide Inversée, a skylight constructed in an underground shopping mall in front of the Louvre Museum in France
- Lady Parry Island, an uninhabited island in Nunavut, Canada, in the Gulf of Boothia
- Organizations
- Lunar and Planetary Institute, a scientific research institute dedicated to study of the solar system, its formation, evolution, and current state
- Linux Professional Institute, a non-profit organization that provides vendor-independent professional certification for Linux system administrators and programmers
- LPI Media, gay and lesbian publisher in the United States
- Science and technology
- Liquid penetrant inspection, also called liquid penetrant inspection (LPI) or penetrant testing (PT), is a widely applied and low-cost inspection method used to locate surface-breaking defects in all non-porous materials (metals, plastics, or ceramics)
- Lysinuric protein intolerance, an autosomal recessive metabolic disorder affecting amino acid transport
- Liquid propane injection
- Liquid phase injectors
- Indexes
- Language Proficiency Index, a Canadian standardized test for English proficiency written and administered by the University of British Columbia Applied Research and Evaluation Services
- Limited Price Indexation, a pricing index used in the calculation of increases in certain components of scheme pension payments in the UK
- Living Planet Index, an indicator of the state of global biological diversity, based on trends in vertebrate populations of species from around the world
- Legatum Prosperity Index, an annual ranking developed by the Legatum Institute of 110 countries, according to a variety of factors including wealth, economic growth, personal wellbeing, and quality of life. Norway topped the list of the 2010 report
- Other uses
- Licensed Private Investigator, a person who can be hired by individuals or groups to undertake investigatory law services
- Linear partial information, a method of making decisions based on insufficient or fuzzy information
- Lines per inch, a measurement of printing resolution in systems that use a halftone screen. Specifically, it is a measure of how close together the lines in a halftone grid are. Higher LPI indicates greater detail and sharpness
- Low probability of intercept Radar (LPIR), a radar system designed to be difficult to detect
- La Paz Incident, occurred in May 1863 at the ghost town of La Paz in Confederate Arizona and was the westernmost confrontation of the American Civil War