The A21RB was a Swedish jet ground-attack aircraft manufactured by Saab in the early 1950s. Following World War II, the Swedish Air Force and Saab became interested in jet aircraft when the piston-engine J21A was just beginning to roll off the assembly line in large numbers. Consequently, they immediately scrapped the project for an improved J21B with a more powerful piston engine and better aerodynamics, and Saab began looking for a jet engine supplier. The British responded with their Goblin engine. It was determined that it would be easier to install the engine in an existing aircraft, the Saab 21, which turned out to be the case. The first prototypes took flight in 1947, and the J21RA entered production in 1949. In the early 1950s, an attack variant, A21RB with a more powerful Goblin III engine was developed. Starting in July 1950, 30 aircraft were built and remained in service with the Swedish Air Force until the 1950s, though they did not participate in combat operations.

The A21RB was introduced in Update 1.95 "Northern Wind". It stands out for its good maneuverability and powerful armament, but suffers from a weak engine and low speed limit.