The Mitsubishi Saturn or 4G3 engine is series of overhead camshaft (OHC) straight-four internal combustion engines introduced by Mitsubishi Motors and saw first service in the 1969 Colt Galant. Displacement ranges from 1.2 to 1.8 L, although there was also a rare 2-litre (1,994 cc) inline-six version built from 1970 until 1976. The early versions have chain driven valvetrain while the later versions are belt driven and equipped with balance shafts.

Mitsubishi Motors Corporation is a Japanese multinational automobile manufacturer headquartered in Minato, Tokyo, Japan. In 2011, Mitsubishi Motors was the sixth-largest Japanese automaker and the 19th-largest worldwide by production. Since October 2016, Mitsubishi has been one-third (34%) owned by Nissan, and included in the Renault–Nissan–Mitsubishi Alliance.