An SG file is a game ROM file used by SG-1000 emulators, such as MasterGear, MESS, and Kega Fusion. It contains a copy of the game data dumped from the original game cartridge.

SG-1000 emulators allow users to play SG-1000 games on a computer or mobile device as if they were run on the original system. Game data from the original SG-1000 game cartridge is dumped into an SG file, which stores the game data in a format that can be played by an SG-1000 emulator. SG-1000 was the first video game console created by Sega. It was released in 1983, primarily in Japan and Australia. SG-1000 game titles include Congo Bongo, Girl's Garden, Sega-Galaga, and Flicky.