The Mitsubishi Colt 800 is the first of a series of passenger cars with a fastback/hatchback design produced by Mitsubishi Motors from November 1965. It was introduced as a two-door fastback sedan, the first such design in the Japanese market. The series was discontinued in 1971, after the introduction of the company's Galant sedan but without a real replacement.

A fastback is an automotive styling feature, defined by the rear of the car having a single slope from the roof to the tail.