The Sega Master System is an 8-bit cartridge-based video game console that was manufactured by Sega and was first released in 1986. Its original Japanese incarnation was the SG-1000 Mark III. In the European market, this console launched Sega onto a competitive level comparable to Nintendo, due to its wider availability, but failed to put a dent in the North American and Japanese markets. The Master System was released as a direct competitor to the NES/Famicom. Despite its shaky performance in the major territories, it has enjoyed over a decade of life in smaller markets.

The later Sega Game Gear is effectively a hand-held Master System, with a few enhancements.