| ls | LayaAir Scene Data |
| ls | Lightscape Solution File |
| ls | Lightwave 3D LScript Data |
| ls2 | LabSat 2 Data |
| ls3 | Band-in-a-Box Third-Party Styles |
| ls3 | Magic Bullet Looks Package |
| ls3w | LabSat 3 Wideband Data |
| ls8 | LISREL 8 Syntax Data |
| lsa | Lightscape ASCII Data |
| lsa | Lotus Domino Agent Script |
| lsb | Lightscape Binary Data |
| lsc | Light-O-Rama Schedule File |
| lsc | LOGO!Soft Comfort Circuit File |
| lsd | ABBYY Lingvo Dictionary User Dictionary |
| lsdx | Apex Z3 Lighthouse Secure Data |
| lse | Oracle Utilities Load Analysis Input |
| lsf | LISREL System Data |
| lsf | Logos Library System Book Data |
| lsg | LimeSurvey Group Structure XML |
| lsgfx | Livestream Studio Graphics Data |
| lsi | SAP Business Objects Local Security Information File |
| lsim | LogicSim Circuit |
| lsl | LightScribe Label |
| lslang | Ad-Aware Language Data |
| lslibrary | LittleSnapper Library Package |
| lsn | MakeMusic Finale Lesson |
| lso | BHV Tonstudio Platin Data |
| lsopt | LS-OPT Data |
| lsp | Audacity LSP Data |
| lsp | LANsurveyor Poll List |
| lsq | CRYSTALS Isotropic Refinement Data |
| lsq | PaleoMag Least Squares Data |
| lsq | ZOOM MRS-802 Phrase Loops Data |
| lsr | LANsurveyor Report |
| lssave | Memory Hacking Software Saved Memory Data |
