Depression in adults has been linked to reduced bone mineral density (BMD), osteoporosis, and increased incidence of fractures. Physiologic factors, such as hypothalamic-pituitary-adrenal axis dysfunction and increased circulation of inflammatory cytokines, may adversely impact bone metabolism. In addition, behavioral factors, such as reduced physical activity and altered dietary intake (especially of bone-related nutrients such as calcium and vitamin D), may be implicated. Antidepressant medications also may have an impact on BMD. Childhood and adolescence may be times of particular vulnerability to the adverse effects of depression due to the rapid bone mineral accrual that occurs during periods of growth. This article will review potential contributing factors and resulting consequences of depression on BMD in these populations and also explore areas of needed research.