| Acronym | Definition |
|---|
| SAI | Statement of Additional Information (SEC) |
| SAI | Silicon Alley Insider, Inc. (website) |
| SAI | Social Accountability International |
| SAI | Sigma Alpha Iota (women's music fraternity) |
| SAI | Sternberg Astronomical Institute |
| SAI | Science Applications International Corporation (stock symbol) |
| SAI | Sports Authority of India |
| SAI | South American Indian (language) |
| SAI | Supreme Audit Institution (Republic of Korea) |
| SAI | Sweet Adelines International (International Organization of Women Barbershop Singers) |
| SAI | Sistema de Alimentacion Ininterrumpida (Spanish: uninterruptible power supply) |
| SAI | Sailfish (FAO fish species code) |
| SAI | Standards Australia International Ltd. |
| SAI | Strategic Agricultural Initiative |
| SAI | Serving Area Interface |
| SAI | Silent Aircraft Initiative (Massachusetts Institute of Technology, Cambridge) |
| SAI | Steering Axis Inclination |
| SAI | Senior Army Instructor |
| SAI | Secondary Air Injection (automotive) |
| SAI | Securities America, Inc. |
| SAI | Systems Applications International |
| SAI | South African Infantry (South African ground troops in World War I) |
| SAI | Self-Administered Interview |
| SAI | Sparse Approximate Inverse |
| SAI | Service Argos Inc. |
| SAI | Specific Area of Interest |
| SAI | Security Awareness Index |
| SAI | Slowly Adapting Type I |
| SAI | Sua Altezza Imperiale (Italian: His/Her Imperial Highness; codices and manuscripts) |
| SAI | Server Availability Index |
| SAI | Systems Architecture and Interfaces (Aeronautical Radio Incorporated) |
| SAI | Standby Attitude Indicator |
| SAI | Structural Adequacy Index (pavement assessment) |
| SAI | Systems Application Integration |
| SAI | Supersonic Aerospace International LLC |
| SAI | Southern Aeroparts Inc. (Tulsa, OK) |
| SAI | Standard Advertising Invoice |
| SAI | Sugar Association, Inc. |
| SAI | Sea-to-Air Interface |
| SAI | Safety Appliance Illustration |
| SAI | single agency item (US DoD) |
| SAI | Swales Aerospace Inc. (Beltsville, Maryland) |
| SAI | Semi-Automatic Interface |
| SAI | Simplified Ab Initio Method |
| SAI | Secretariat al'Adoption Internationale |
| SAI | Solution Assay Instrument |
| SAI | Strategic Command Administrative Instruction (USSTRATCOM) |
| SAI | Sequential Action Interaction |
| SAI | Spanish Artificial Intelligence |
| SAI | Surveillance-Aided Intercept |
| SAI | Sahawa al Iraq |
| SAI | Square-And-Integrate |
| SAI | Spectrum Astro Incorporated (Phoenix, Arizona) |
| SAI | Strength and Integrity Inspection (US Navy 5 year boiler inspection) |
| SAI | Situation Awareness Infrastructure |
| SAI | Standardization, Analysis, and Integration Branch |
| SAI | Smart Animal Identification (workshop) |
| SAI | Studio Associato Immobiliare (Italian: Associated Real Estate Study) |
| SAI | Scaled Aviation Industries Limited (Pakistan) |