Motocross is a form of motorcycle sport or all-terrain vehicle racing held on enclosed off road circuits. Motocross is derived from the French, and traces its origins to British scrambling competitions. The name "motocross" is a portmanteau derived from the words "Motorcycle" and "Cross Country".

Motocross was first known as a British off-road event called scrambling, which was an evolution of motorcycle trial events popular in the northern UK. The first known scramble took place at Camberley, Surrey in 1924. During the 1930s, the sport grew in popularity, especially in Britain where teams from the Birmingham Small Arms Company (BSA), Norton, Matchless, Rudge, and AJS competed in the events. Off-road bikes from that era differed little from those used on the street. The intense competition over rugged terrain led to technical improvements in motorcycles. Rigid frames gave way to suspensions by the early 1930s, and swinging fork rear suspension appeared by the early 1950s, several years before it was incorporated on the majority of production street bikes . The period after the Second World War was dominated by BSA which had become the largest motorcycle company in the world . BSA riders dominated international competitions throughout the 1940s.