File with a .THEMEPACK extension contains theme – a CAB pack of elements which personalises Windows system 7, such as wallpaper, windows interface settings, cursors, icons, sounds or screensavers. They enable to share system themes, because all of the files (including those with graphic and sound) are contained within a single package, unlike the THEME files, in which the appearance settings are defined with text but they do not contain, for instance, the desktop.

THEMEPACK files are characteristic only to Windows 7, later versions can use them, but Windows 8 stores desktop compositions in files with .DESKTHEMEPACK extension. The content of a THEMEPACK file can be opened with any tool enabling unpacking CAB packages (for instance: WinZip or 7-Zip). Loading of themes is possible with the Personalisation tool available in the Control Panel of Microsoft Windows 7.