SLI may stand for:
- Scalable Link Interface, NVIDIA's method for connecting two or more video cards together to produce a single output
- Scan-Line Interleave, 3dfx's method for connecting two or more video cards together, predecessor to Scalable Link Interface
- Safe Load Indicator in cranes
- SAP Labs India, the Indian subsidiary of SAP AG
- In Socionics, a Sensory Logical Introvert
- Shipper's Letter of Instruction, used in the process of transporting goods; could be a supplemental document as part of an Air waybill
- SLI Systems, Search, Learn and Improve Systems, a search engine that learns from its users
- The Somerset Light Infantry (Prince Albert's), a former regiment in the British Army
- Space Launch Initiative
- Specific language impairment, a language disability that runs in families
- Starting - Lighting - Ignition battery, a term used for a car battery
- Street light interference, a phenomenon whereby street lights appear to go out as one passes beneath them
- Swiss Leader Index, a market index on the Swiss Stock Exchange
- Sylvania Lighting International
- Symmetric level-index arithmetic, a computer arithmetic which is used to overcome the problems of overflow and underflow in scientific computing