| spl | Windows Spool Data |
| spl | Abacom sPlan Components Database |
| spl | AkAbak Simulation Data |
| spl7 | Abacom sPlan 7 Circuit Diagram |
| splan | SPSS Statistics Simulation Plan |
| splf | SecureZIP Spool File |
| spm | Nanoeducator File |
| spmo | SpeedView Meta Object |
| spn | GSSHA Storm Pipe Network |
| spn | PC-SPAN SPAN Data |
| spo | SPSS Statistical Output |
| spo | SPOCK External Objects Data |
| spq | SPSS Saved ODBC Query |
| spr | ArchiCAD Slab Properties |
| sprf | Manip Saved Proof File |
| sps | SPSS Syntax File |
| spub | BeLight Disc Cover Data |
| spud | iGO Primo SpeedCam Database Update |
| spv | SPSS Output Document |
| spvchain | MultiBit Locally Stored Blockchain |
| sq3 | SQLite 3 Database |
| sq7 | Daktronics Venus 7000 Sequence Data |
| sqb | SQL Backup SQL Server Backup |
| sqd | FidoNet Squish Data |
| sqd | Sysquake SQ Data |
| sqg | SeQuence Graph Data |
| sqi | FidoNet Squish Index Data |
| sql | SQL Script |
| sql | FidoNet Squish Lastread Storage |
| sqlite | SQLite Database |
| sqlite3 | SQLite 3 Database |
| sqlitedb | SQLite Database |
| sqlt | SQLite Database |
| sqm | Microsoft Message Queuing Data |
| sqp | Sonique Audio Search Query Result Data |
