SPI
SPI may refer to:

Organizations
Indian Protection Service (Serviço de Proteção ao Índio), Brazil
Shotmed Paper Industries, an Egyptian paper manufacturers
Simulations Publications, Inc., a former US board game publisher
Sony Pictures Imageworks
Stream Processors, Inc, a semiconductor company
Sisters of Perpetual Indulgence, an LGBT  group
Society for Philosophical Inquiry
Society of the Plastics Industry, a U.S. trade association
Software in the Public Interest
Software Patent Institute, US
St. Pascual Institution, Philippines school
St. Paul's Institution, a school in Malaysia
Sustainable Preservation Initiative, of cultural heritage
Sveriges Pensionärers Intresseparti, or Swedish Senior Citizen Interest Party
Social Progress Imperative, a US-based nonprofit created in 2012

Computing
SCSI Parallel Interface
Serial Peripheral Interface
Security Parameter Index in IPSec tunneling
Service provider interface, an API
Software Process Improvement, of Data & Analysis Center for Software
System Packet Interface for networking
Stateful Packet Inspection for networking

Other uses
Schedule Performance Indicator, a performance indicator within project management
Single-point injection
Social Progress Index of countries
Abraham Lincoln Capital Airport (IATA code), US
Sediment Profile Imagery underwater
South Padre Island, a resort town in Cameron County, Texas
Spi-calculus, a proposed extension of Π-calculus
Swiss Performance Index, a stock index

See also
SPI 200 futures contract, Australian index
Spy (disambiguation)