Bicycle motocross, or BMX, is a sport involving bicycles that race in a motocross style on tracks with obstacles, starting from a starting line.

BMX originated in the early 1970s in Southern California, when children, inspired by the motocross stars of the era, began racing their bicycles on dirt tracks. BMX racing was an unusual phenomenon in the mid-1970s. Teenagers and children raced around specially designed tracks in California on standard road bicycles over uneven terrain. They imitated motocross races, competing against each other on rough tracks while wearing motocross-style clothing. In 1972, the documentary film On Any Sunday, dedicated to motorcycle racing, helped inspire a national movement in the United States. Its opening scene depicted children riding Sting-Race bicycles on rough tracks. By the mid-1970s, the sport had gained significant popularity, and manufacturers began designing bicycles specifically for BMX. BMX was included in the program of the International Olympic Committee in 2003 and made its Olympic debut at the 2008 Beijing Summer Olympics, with competitions for both men and women. The first Olympic champions in BMX were Maris Štrombergs from Latvia for men and Anne-Caroline Chausson from France for women. On May 28, 2011, 24-year-old BMX rider Ced Mildon set a world record by performing a triple backward somersault on a BMX bicycle.