| gyp | Chromium GYP Language File |
| gypi | Chromium GYP Language Include |
| h | C Header File |
| h2 | H2 Database File |
| h86 | µVision Intel HEX Data |
| hac | Helma Actions Script |
| hal | HansaWorld Hansa Applications Language File |
| ham | HAM Executable File |
| haml | Haml Source Code |
| handlebars | Handlebars Template |
| has | Haskell Script |
| hbs | Handlebars Template |
| hcf | Compact HAM Library |
| hdcl | Hierarchical Dynamic Composition Language Document |
| hdmp | Windows Heap Dump |
| hdx | Delphi MultiHelp Index |
| hei | Heitml Source Code |
| hen | HEN Project |
| het | WinSQL HTML Export Template |
| hex | Intel HEX Format Data |
| hg | GNOME C++ Header |
| hg | Mercurial Data |
| hh | HTML Help Header File |
| hh | C++ Header File |
| hhc | HTML Help Table of Contents |
| hhh | Power C Precompiled Header |
| hhk | HTML Help Index |
| hi | Haskell Interface |
| hic | HicEst Script |
| hie | GHC HI Extended |
| hiro | ARToolKit Hiro Marker Data |
| hj | Habanero-Java Source Code |
| hkk | HTML Help AutoIndex |
| hks | HTML-Kit Script |
| hla | High Level Assembly Source Code |