| Acronym | Definition |
|---|
| SPI | Service Provider Interface |
| SPI | Security Parameter Index |
| SPI | South Padre Island (Texas) |
| SPI | Stateful Packet Inspection (firewall based protocol) |
| SPI | Software Process Improvement |
| SPI | Society of the Plastics Industry |
| SPI | Software in the Public Interest, Inc |
| SPI | Seattle Post Intelligencer (Newspaper) |
| SPI | Soy Protein Isolate |
| SPI | Superintendent of Public Instruction (Washington State) |
| SPI | Smart Plug-Ins |
| SPI | Schedule Performance Index |
| SPI | Sciences pour l'Ingénieur (French: Engineering Science; university course) |
| SPI | SCSI Parallel Interface |
| SPI | Swiss Performance Index (trademark of SWX Swiss Exchange) |
| SPI | Sony Pictures Imageworks |
| SPI | Standardized Precipitation Index |
| SPI | Systems Products International |
| SPI | Società Psicoanalitica Italiana |
| SPI | Share Price Index (weighted index of Australian share prices) |
| SPI | Servizi per l'Impiego (Italian: Employment Services) |
| SPI | Simulations Publications Inc (game company) |
| SPI | Syndicat des Producteurs Indépendants (French: Union of Independent Producers) |
| SPI | Single Process Initiative |
| SPI | System Packet Interface |
| SPI | Software Patent Institute |
| SPI | Svenska Petroleum Institutet (Swedish Petroleum Institute) |
| SPI | System Programming Interface |
| SPI | Sisters of Perpetual Indulgence (aka Order of Perpetual Indulgence) |
| SPI | SmartPlant Instrumentation (Intools) |
| SPI | Southern Police Institute |
| SPI | Security Profile Inspector |
| SPI | Single Point Injection |
| SPI | Social Performance Indicators |
| SPI | Strategic Planning Initiative |
| SPI | Space Policy Institute (George Washington University) |
| SPI | Single Page Interface (web pages) |
| SPI | Studio Progettazione Immagine (Italy; website development and marketing company) |
| SPI | Security Policy Initiative |
| SPI | Small Parts, Inc. |
| SPI | Statutory Performance Indicator |
| SPI | Sciences Physiques pour l'Ingénieur (French: Physical Sciences for the Engineer) |
| SPI | Society of Professional Investigators |
| SPI | Spectrometer on Integral |
| SPI | Spots Per Inch |
| SPI | Senior Photographers International (Venice, FL) |
| SPI | Self-Paced Instruction |
| SPI | Segment Play Items |
| SPI | Strategic Planning and Information |
| SPI | Sow Productivity Index |
| SPI | Significant Performance Impact |
| SPI | Shipping Point Inspection |
| SPI | Strategic Profits Inc |
| SPI | Springfield, IL, USA - Capital Airport (Airport Code) |
| SPI | Standard Practice Instruction |
| SPI | Software Paradigms Infotech, Pvt. Ltd. (various locations) |
| SPI | Safeguard Against Privacy Invasions (anti-spyware act) |
| SPI | Sojuzplodimport |
| SPI | Subsequent Protocol Identifier |
| SPI | Software Process Innovations |
| SPI | SDH Physical Interface |
| SPI | System Property Intervals |
| SPI | Ship/Port Interface |
| SPI | Subsystem Programmatic Interface |
| SPI | Source Potential Index |
| SPI | Special Position Identifier (aircraft transponder Mode A capability) |
| SPI | Service Performance Indicator |
| SPI | Surface Position Indicator |
| SPI | Sites Pédagogiques Indépendants (French: Independent Educational Sites) |
| SPI | Synchronous Physical Interface |
| SPI | Sierra Pacific Innovations Corp. (Las Vegas, NV) |
| SPI | Stroke Prevention Initiative |
| SPI | Software Piracy Intervention |
| SPI | Syngenta Philippines Inc. (Makati City, Philippines) |
| SPI | Stub Programming Interface |
| SPI | Sequential Port Injection |
| SPI | Special Processing Indicator |
| SPI | Spiral Point of Intersection |
| SPI | Single Program Initiator |
| SPI | Standard Programmatic Interface |
| SPI | Signal Propagation of Interconnects (IEEE workshop) |
| SPI | Sexual Preference Insult |
| SPI | Science Program Implementation |
| SPI | Semi-Autogenous Grining Power Index |
| SPI | Shared Programming Interface (SunCom) |
| SPI | Shreveport Paranormal Investigations (Louisiana) |
| SPI | Software Property Inventory (USACE) |
| SPI | Shipping Procedural Instructions |
| SPI | Special Personnel Insertion (Rigging) |
| SPI | Scheduled and Pending Inventory |
| SPI | Sysware Philippines Inc (Republic of the Philippines) |
| SPI | Situational Problem Input |
| SPI | System Programmable Interrupt |
| SPI | Shell Process Infrastructure |
| SPI | Special Packaging/Processing Instruction(s) |
| SPI | Société de Peinture Industrielle (French: Industrial Painting Company) |
| SPI | Softpro India (Computer Technologies Pvt Ltd) |
| SPI | Strategic Psychological Intelligence (trademark of Boswell Group) |
| SPI | Silverstein Properties, Inc. (est. 1957; various locations) |
| SPI | Second Palestinian Intifada |
| SPI | Sensor Products Inc (East Hanover, New Jersey) |
| SPI | Student Press Initiative |
| SPI | South Panafrican International (Togo) |
| SPI | Socialist Party of Ireland (political party) |
| SPI | Society for Philosophical Inquiry |
| SPI | Swiss Post International |
| SPI | State Pedagogical Institute (various locations) |
| SPI | Solar Power, Inc. (Rosewall, CA) |
| SPI | Sensitive Personal Information (privacy) |
| SPI | Suicide Prevention International (New York, NY) |
| SPI | Structural Pest Inspector |
| SPI | Society of Practitioners of Insolvency (UK) |
| SPI | Sales Price Increase |
| SPI | Solder Paste Inspection (circuit boards) |
| SPI | Serial Peripheral Interface |