HME is an extension given to files that are used in the system for Windows Mobile devices. The HME file is used to store themes for this system. These files are responsible for the appearance of the user interface. These can be, for example, the background or the transparency of the tiles, the colors of individual elements, wallpapers, etc. A certain number of themes are pre-installed with the system on the device.

HME files can also be created by the user using the Theme Generator tool developed by Microsoft.