Vitamin D deficiency has suggested that not only a biochemical abnormality, but is also associated with adverse effect of poor bone mineralization in growing children and adolescents. The findings of the present study clearly demonstrate that vitamin D deficiency occurs in a high proportion of adolescent girls, regardless of what 25(OH)D level is used to define vitamin D deficiency. In addition, body mass index (BMI), milk intake, participation in organized sports and total physical activity all emerged as major determinants of vitamin D status. The relationship between vitamin D status and bone mass and bone biomarkers showed that girl participants with a higher vitamin D status had significantly higher bone mass at the total body and distal and proximal forearm, and higher concentrations of IGF-I, lower concentrations of BAP and a lower urine Dpd/creatinine ratio compared to those of poor vitamin D status. Therefore, continuous participation in high physical activity, and adequate vitamin D status throughout childhood and late adolescence could help achieve maximum peak bone mass at maturity and thus reduce the risk of osteoporotic fractures later in life.