The Steyr XX is a car which was made by Steyr in 1929. It was introduced as the successor to the Steyr XII.

The car was developed by Anton Honsig designed.

The car had a 2070cc 6-cylinder in-line engine that produced 40hp. The car was fitted with a four-speed manual gearbox and power was sent to the rear wheels. The front wheels were mounted on a rigid axle and longitudinal leaf springs. The rear swing axle had a transverse leaf spring.

In the single year of production 2900 cars were made.