Free solo climbing, or free soloing, is a form of rock climbing where the climbers climb solo without ropes or other protective equipment, using only their climbing shoes and their climbing chalk. Free soloing is the most dangerous form of climbing, and, unlike bouldering, free soloists climb above safe heights, where a fall can be fatal. Though many climbers have free soloed climbing grades they are very comfortable on, only a tiny group free solo regularly, and at grades closer to the limit of their abilities.

Solo climbing, or soloing, is a style of climbing in which the climber climbs a route alone, without the assistance of a belayer. By its very nature, it presents a higher degree of risk to the climber, and in some cases, is considered extremely high risk. Note that the use of the term "solo climbing" is generally separate from the action of bouldering, which is itself a form of solo climbing, but with less serious consequences in the case of a fall. The most dangerous form of solo climbing is free solo climbing, which means both climbing alone and without any form of climbing protection.