OMOD are files used by an RPG game called Elder Scrolls IV: Oblivion and Fallout 3. OMOD is a compressed archive using the 7Z format that stores modifications to the game. Installing such a file to the correct game, depending on the content, allows you to change the functionality of some elements in the game and their appearance. These can be, for example, weapon upgrades, character appearance or new gameplay elements.

OMOD files are supported by Oblivion Mod Manager. Mod files can also have other extensions.