A sidecar motorcycle is a three wheel vehicle with the sidewheel not directly aligned with the rear motorcycle wheel, and is usually powered by the rear wheel only. This is different from a motorcycle trike, where both rear wheels are powered and share a common axle. However, either P.V. Mokharov of the Soviet Union or H.P Baughn of Great Britain seem to have to been the first to employ a driven sidecar wheel in 1929. In fact Baughn 2WD outfits were so successful in trials events in the early 1930s that there were attempts to have the ACU to ban them from competition. A great many companies experimented with 2WD in sporting events and indeed many companies employed them in military vehicles prior to the commencement of WWII.

There are numerous categories of racing for sidecars.

These are generally broken down into two major disciplines - Historic and Modern.