The Mazda 121 name has been used on different types of automobiles sold by Mazda of Japan since 1975.

Between 1975 and 1981, it was used for a large coupé known as the Mazda Cosmo in Japan and North America.

Later, the Mazda 121 name was used for a subcompact car sold by Mazda. A version of the original 121 was produced by Kia in South Korea, and sold in North America, East Asia, and Australasia as the Ford Festiva. It was also sold in South Korea and other markets as the Kia Pride.

The 1985 121 was available with three engines:

• 1138cc SOHC, 56 hp (42 kW)/65 ft.lbf (88 Nm)
• 1324cc SOHC, 71x83.6mm, 65 hp (48.5 kW)/77 ft.lbf (105 Nm)
• 1290cc DOHC, 88 hp (66 kW)/72 ft.lbf (98 Nm)

• Wheelbase: 2295 mm
• Length: 3475 mm
• Width: 1605 mm
• Weight: 725 kg

In 1989, the Mazda 121 name was applied to the Autozam Revue, a subcompact four-door sedan. The Ford and Kia versions continued unchanged although Ford got a new version, on the same platform, for the 1994 model year (sold as the Ford Aspire in North America). The same model was called the Kia Avella in South Korea.

In 1996, the name was shifted to export versions of the Mazda Demio, a tall, five-door hatchback also known as the Ford Festiva Mini Wagon in Japan.

In Europe, the Japanese sourced model was replaced by a rebadged Ford Fiesta the same year.

The 121 has since been replaced by the Mazda Mazda2, which is built on the same platform as the Fiesta and the European version of the Fusion.