SOI
- Chua Soi Lek
- DO-178C
- DO-254
- Microsoft text-to-speech voices
- Pou-Soi
- SOJ (disambiguation)
- School of Infantry
- Second-order intercept point
- Service-oriented infrastructure
- Severity of illness
- Shadow of Israphel
- Signal operating instructions
- Silicon on insulator
- Sociosexual Orientation Inventory
- Soi (surname)
- Soi language
- Soia (disambiguation)
- Soja (disambiguation)
- Solomon Islands
- Southern Oscillation Index
- Soy (disambiguation)
- Soya (disambiguation)
- Sphere of influence
- Sphere of influence (astrodynamics)
- Stars on Ice
- Statistics of Income
- Symphony Orchestra of India