| knk | KNK Studio Cutting Docment |
| knt | iWork Keynote Note Document |
| kpp | Kid Pix Presentation |
| kpr | KPresenter Presentation |
| kpx | Kid Pix Picture |
| krs | GEUS Document |
| ks3 | 3D Forgastest Editor Object |
| ksw | Kepler Workflow Document |
| kte | FoilMaker Kite Design |
| kth | iWork Keynote Theme |
| kvtml | KWordQuiz Document |
| kw3 | KanjiWORD 3 Document |
| kwd | KWord Document |
| kwl | Kamban Word Processor Lite Document |
| kwp | Kamban Word Processor Document |
| l3b | SR 3D Builder Model |
| laccdb | Microsoft Access 2007 Database Lock |
| latex | LaTeX Document |
| law | eLawForms Form Document |
| lay | Sprint-Layout Document |
| lay6 | Sprint-Layout v6 Document |
| lbi | Dreamweaver Library |
| lbl | Broderbund PrintMaster Label |
| lbl | P-touch Editor Document |
| lbx | P-touch Editor v5 Document |
| lbz | Leibniz Document |
| lch | IBM Works for OS/2 Chart |
| lcm | Label Designer Plus Document |
| lcw | Lucid 3-D Spreadsheet |
| ldf | Luratech Portable Document |
| ldr | LDraw Model File |
| leg | LEGO CAD Model Data |
| lep | Label Designer Plus Document |
| let | Broderbund PrintMaster Letterhead |
| lgf | Imagine LogoMotion Image |