File extensions start with character 'L'
| File Type | Category | File Format | |
|---|---|---|---|
| .l6t | Data Files | Line 6 Tone File | |
| .lab | Page Layout Files | WordPerfect Label Definition File | |
| .laccdb | Microsoft Files | Microsoft Access Lock File | |
| .lang | Settings Files | Minecraft Language File | |
| .latex | Text Files | LaTeX Document | |
| .lay | Multiple Use Files | DVD Studio Pro Layout File | |
| .layout | Configuration Files | Code::Blocks Workspace Layout File | |
| .lbl | Database Files | NiceLabel Template File | |
| .lbr | Lotus Driver Files | LU Library Archive | |
| .lbt | Text Files | FoxPro Label Memo | |
| .lcf | CAD Files | ArchiCAD Library Container File | |
| .lck | Multiple Use Files | Program Lock File | |
| .ldb | Multiple Use Files | Microsoft Access Lock File | |
| .ldf | Data Files | SQL Server Transaction Log File | |
| .ldm | Volume Files | VolumeViz Multi-Resolution Volume File | |
| .ldt | CAD Files | Eulumdat Formatted Luminaire Data File | |
| .lemon | Compressed Files | LemonShare.net Download | |
| .lfo | Configuration Files | Alchemy Low Frequency Oscillator Presets File | |
| .lgo | Development Files | Logo Instructions File | |
| .lha | Compressed Files | LHARC Compressed Archive | |
| .lib | Microsoft Files | Generic Data Library | |
| .lic | Multiple Use Files | Software License File | |
| .lip | SLIP Files | Bethesda Softworks Lip Sync File | |
| .lis | Text Files | SQR Output File | |
| .list | Development Files | JAR Index File | |
| .lit | eBook Files | eBook File | |
| .lix | Data Files | Logos Library System File | |
| .llb | Data Files | LabVIEW Library File | |
| .lmk | Vector Graphics Files | Sothink Logo Maker Image | |
| .lms | Data Files | LenMus Score File | |
| .lmx | Data Files | Landmark Exchange File | |
| .lng | Language Defnition Files | Language Application Support File | |
| .lnk | Windows System Files | Windows File Shortcut | |
| .loc | Data Files | GPS Location File | |
| .localstorage | Google Files | WebKit Local Storage Data File | |
| .lock | Multiple Use Files | Lock File | |
| .lod | Google Files | Heroes of Might and Magic 3 Graphics File | |
| .log | Log Files | Log File | |
| .log1 | Registry Files | Windows Registry Hive Log File | |
| .lp7 | Data Files | LP7 Digitally Signed File | |
| .lpdb | Data Files | Librarian Pro Database File | |
| .lpk | Package Files | ArcGIS Layer Package | |
| .lqr | Compressed Files | SQ Compressed LBR Archive | |
| .lrcat | Data Files | Adobe Photoshop Lightroom Catalog File | |
| .lrdata | Data Files | Adobe Photoshop Lightroom Data File | |
| .lrec | Digital Video Files | Inter-Tel Web Conference Recording | |
| .lrf | eBook Files | Sony Portable Reader File | |
| .lrs | eBook Files | Librie Reader Source File | |
| .lrtemplate | Configuration Files | Adobe Photoshop Lightroom Template | |
| .lrx | eBook Files | Sony Portable Reader File | |
| .lsl | Data Files | LightScribe Label | |
| .lsp | Development Files | Lisp Program Source Code File | |
| .lsr | Data Files | LANsurveyor Report | |
| .lst | Text Files | Data List | |
| .lsu | Data Files | LANsurveyor Map | |
| .ltr | Text Files | Letter File | |
| .ltx | Text Files | LaTeX Document | |
| .lua | Development Files | Lua Source File | |
| .lue | Text Files | Norton LiveUpdate Log File | |
| .luf | Text Files | Lipikar Uniform Format File | |
| .lvm | Data Files | LabVIEW Measurement File | |
| .lvw | Data Files | Livewire Document | |
| .lw4 | Data Files | Lightwright File | |
| .lwp | Text Files | Lotus Word Pro Document | |
| .lxf | XML Data Files | LEGO Digital Designer Model File | |
| .lxfml | Text Files | LEGO Digital Designer XML File | |
| .ly | Data Files | LilyPond File | |
| .lyc | CAD Files | bestIMAGE Compressed Design File | |
| .lyr | Multiple Use Files | ArcView Layer File | |
| .lyt | Configuration Files | Xcalibur Layout File | |
| .lyx | Text Files | LyX Document | |
| .lz | Compressed Files | Lzip Compressed File | |
| .lzh | Compressed Files | LZH Compressed File | |
| .lzm | Compressed Files | Slax Module | |
| .lzma | Compressed Files | LZMA Compressed File | |
| .lzo | Compressed Files | LZO Compressed File | |
| .lzx | Compressed Files | Amiga LZX Compressed File |