The role of leg length discrepancy (LLD) both as a biomechanical impediment and a predisposing factor for associated musculoskeletal disorders has been a source of controversy for some time. LLD has been implicated in affecting gait and running mechanics and economy, standing posture, postural sway, as well as increased incidence of scoliosis, low back pain, osteoarthritis of the hip and spine, aseptic loosening of hip prosthesis, and lower extremity stress fractures. Authors disagree on the extent (if any) to which LLD causes these problems, and what magnitude of LLD is necessary to generate these problems. This paper represents an overview of the classification and etiology of LLD, the controversy of several measurement and treatment protocols, and a consolidation of research addressing the role of LLD on standing posture, standing balance, gait, running, and various pathological conditions. Finally, this paper will attempt to generalize findings regarding indications of treatment for specific populations.