Bicycles have been ridden off-road since their invention. However, the modern sport of mountain biking primarily originated in the 1970s . There were several groups of riders in different areas of the U.S.A. who can make valid claims to playing a part in the birth of the sport. Riders in Crested Butte, Colorado and Cupertino, California tinkered with bikes and adapted them to the rigors of off-road riding. Other riders around the country were probably copying their friends with motorcycles and riding their bikes on trails and fire roads. However, a group in Marin County, California is recognized by the Mountain Bike Hall of Fame to have played a central role in the birth of the sport as we know it today. They began racing down Mount Tamalpais (Mt Tam) on old 1930s and '40s Schwinn bicycles retrofitted with better brakes and fat tires. This group included Joe Breeze, Otis Guy, Gary Fisher, and Keith Bontrager, among others. It was Joe Breeze who built the first new, purpose-made mountain bike in 1977. Tom Ritchey built the first regularly available mountain bike frame, which was accessorized by Gary Fisher and Charlie Kelly and sold by their company called MountainBikes (later changed to Fisher Mountain Bikes then bought by Trek, still under the name Gary Fisher). The first two mass produced mountain bikes were sold in 1982: the Specialized Stumpjumper and Univega Alpina Pro.

In 1988, the Mountain Bike Hall of Fame was founded to chronicle the history of mountain biking, and to recognize the individuals and groups that have contributed significantly to this sport.