| Acronym | Meaning |
| SLS | Sequential Lateral Solidification |
| SLS | Sodium Lauryl Sulfate |
| SLS | Static Light Scattering |
| SLS | Strained Layer Superlattice |
| SLT | Standard Leaching Test |
| SMA | Steel Manufacturers Association |
| SMA | Shape Memory Alloy |
| SMA | Specific Methanogenic Activity |
| SMA | Spinal Muscular Atrophy |
| SMAI | Solvated Metal Atom Impregnation |
| SMART | System Integrated Modular Advanced ReacTor |
| SMART | Stimulated Martensite-austenite Reverse Transformation |
| SMART-1 | Small Missions For Advanced Research In Technology-1 |
| SMARTS | SMiles ARbitrary Target Specification |
| SMAW | Shielded Metal Arc Welding |
| SMB | Simulated Moving Bed |
| SMBC | Simulated Moving Bed Chromatography |
| SMBC | Soil Microbial Biomass Carbon |
| SMBG | Self-monitoring Blood Glucose |
| SMBR | Submerged Membrane Bioreactor |
| SMC | Schwinger Multichannel (for Electron-mol. Scattering) |
| SMC | Small Magellanic Cloud |
| SMC | Sheet Molding Compound |
| SMC | Smooth Muscle Cell |
| SMCL | Secondary Maximum Contaminant Level |
| SMCM | Spatial Multimedia Compartmental Model |
| SMCRA | Surface Mining Control And Reclamation Act |
| SMD | Sauter Mean Diameter |
| SMD | Single-molecule Detection |
| SMDE | Static Mercury Drop Electrode |
| SME | Solar Mesosphere Explorer |
| SME | Shape Memory Effect |
| SME | Solid-metal Embrittlement |
| SME | Static Model Exchange (approxn. In Electron-mol. Scattering) |
| SMES | Superconductive Magnetic Energy Storage |
| SMF | Standard Monitoring Framework |
| SMFS | Single Molecule Force Spectroscopy |
| SMG | Submandibular Gland |
| SMIDG | Submicro Inverse-detection Gradient |
| SMIE | Solid-metal-induced Embrittlement |
| SMIL | Synchronized Multimedia Integration Language |
| SMILES | Simplified Molecular Input Line Entry System |
| SMILES | Superconducting Sub-Millimeter-wave Limb Emission Sounder |
| SMILETRAP | Stockholm-Mainz-Ion Levitation Trap |
| SMILI | Superconducting Magnet Instrument For Light Isotopes |
| SML | Surface Microlayer |
| SMLR | Stepwise Multiple Linear Regression |
| SMM | Solar Maximum Mission |
| SMM | Scanning Magnetic Microscopy |
| SMM | Single-molecule Magnet |