| sln | Microsoft Visual Studio Solution |
| slp | Adobe RoboHelp Screen Layout Page |
| slt | Mozilla 1.0 Profile SALT Data |
| Telix Salt Script Source Code |
| slz | Adobe RoboHelp Exported Screen Layout |
| sm2 | Crestron SIMPL Program Backup |
| sma | Counter-Strike AMX Mod Add-on Source Code |
| smali | Android Smali Assembly Source Code |
| smallbasic | Small Basic Source Code |
| smap | JSP Source Map File |
| smcl | Stata SMCL Log |
| smdl | Microsoft SQL Server SMDL Data |
| smft | Crestron SIMPL Autoupdate Manifest Data |
| smpi | LINDO SMPI File |
| smps | LINDO SMPS File |
| smrc | Smtools Repository Data |
| smw | Crestron SIMPL Program |
| smx | IBM Rational XDE SMX Data |
| sn | PG4UW Serialization Data |
| sndsao | Aleph One Sound Data |
| sni | MDK Archive |
| snippet | Visual Studio IntelliSense Code Snippet |
| snk | .NET Strong Name Key |
| sno | Snobol4 Language Source Code |
| snw | Sweave Document |
| so | Unix Shared Library |
| sob | Visual Basic SOB File |
| sof | Altera Quartus II SRAM Object |
| sol | Solidity Script |
| soy | Google Closure Template |
| sp2 | SAS Permanent Utility |
| sp4 | SuperCard Player File |
| sp45 | SuperCard Player File |
| sp7 | SAS Permanent Utility |
| sparql | SPARQL Script |
| spdslog | SAS Scalable Performance Data Server Log |
| spec | RPM Package Specification |
| spk | Artspeak Source File |
| DroidScript Source Code |
| Novell Netware Server Source Package |
| Stampede Linux Simple Packaging Kit |
| spkg | Windows Phone Driver Package |
| splx | SPLX Package |
| spm | Source Package Manager Data |
| TeleFinder Page |
| spml | TeleFinder Page |
| spp | Crestron SIMPL+ Parameters Data |
| spr | Visual FoxPro Form Program |
| sprite | BYOB Sprite |
| Scratch v1 Sprite |
| sprite2 | Scratch v2 Sprite |
| sprite3 | Scratch v3 Sprite Data |
| sprx | Signed PPU Relocatable Executable |
| spt | ESPL Programming File |
| Spitbol Language Source Code |
| spwn | SPWN Geometry Dash Trigger Modifier |
| spx | Visual FoxPro Compiled Form |
| spy | WinTECH Socket Spy Log |
| spyx | SageMath Pyrex Source Code |
| spz | Crestron SIMPL Compiled Program |
| sq | Sysquake SQ Application |
| sqc | SQR Common Code |
| sqlce | Microsoft SQL Server SQLCE Data |
| sqljet | Eclipse JET SQL Template |
| sqml | Standard Query Markup Language Document |
| sqn | SAS for Mac 6 DMDB Database |
| sqo | Squeak Object |
| sqr | SQR Script |
| sqt | Compiled SQR Script |
| squ | NI LabWindows/CVI Test Executive Toolkit Sequence Data |
| sra | Sybase PowerBuilder Application |
| src | General Source Code File |
| ProWorx NXT Search Data |
| WAIS Source File |
| Win32Forth Sequential Block Data |
| srd | Sybase PowerBuilder DataWindow |
| sre | Windows CE Embedded Rom Image |
| srf | Sybase PowerBuilder Functions Data |
| Visual Studio Server Response Data |
| srm | Sybase PowerBuilder Menu |
