SPI may stand for:

In organizations:

  • Shotmed Paper Industries, an Egyptian paper manufacturer
  • Simulations Publications, Inc., an American publisher of board wargames
  • Sony Pictures Imageworks, a visual effects and animation company
  • SPi Technologies, a business outsourcing provider founded in the Philippines
  • Stream Processors, Inc. Stream Processors, Inc. a fabless semiconductor company making parallel processors for embedded markets.
  • Sisters of Perpetual Indulgence, international LGBT non-profit group
  • Society for Philosophical Inquiry, a non-profit organization promoting discussion of philosophy
  • Society of the Plastics Industry, a U.S. trade association
  • Software in the Public Interest, a non-profit organization promoting free and open-source software
  • Software Patent Institute, an American non-profit assisting in the correct assignment of software patents
  • St. Pascual Institution, former name of Colegio de San Pascual Baylon, a school in Obando, Bulacan, Philippines
  • St. Paul's Institution, Seremban, secondary school in Malaysia
  • Sveriges Pensionärers Intresseparti, or Swedish Senior Citizen Interest Party, a political party in Sweden

In finance:

  • SPI 200 futures contract, the benchmark equity index futures contract in Australia
  • Swiss Performance Index, most closely followed stock index in Switzerland

In technology:

  • SCSI Parallel Interface, in physical data transfer, a parallel electrical bus interface
  • Serial Peripheral Interface Bus, a synchronous serial data link standard that operates in full duplex mode
  • Security Parameter Index, in computer networking, an identification tag added to the header
  • Service provider interface, a software mechanism to support replaceable components
  • Software Process Improvement, an initiative of the Data & Analysis Center for Software
  • Stateful packet inspection, the process used by a firewall to keep track of the state of network connections
  • System Packet Interface, family of interfaces from the Optical Internetworking Forum
  • SPI-3, a system packet interface designed to be used in systems that support OC-48 SONET interfaces
  • SPI-4.2, a system packet interface designed to be used in systems that support OC-192 SONET interfaces
  • SharePoint Project Item, a collection of project files in Microsoft SharePoint.

In other:

  • Abraham Lincoln Capital Airport, a Springfield, Illinois airport with IATA code SPI
  • Spi-calculus, a proposed extension of the Pi-calculus