The BM-21 launch vehicle (Russian: БМ-21, (Grad) a Soviet truck-mounted 122 mm multiple rocket launcher,and a M-21OF rocket were developed in the early 1960s.

BM stands for boyevaya mashina, ‘combat vehicle’, and the nickname grad means ‘hail’. The complete system with the BM-21 launch vehicle and the M-21OF rocket has designation as M-21 Field Rocket System. The complete system is more commonly known as a Grad multiple rocket launcher system