Once considered a burgeoning area of clinical care in children, osteoporosis in the young is now recognized as an important facet of child health with sufficient evidence to support standardized approaches to diagnosis, monitoring, treatment and prevention. Current management strategies are based on monitoring at-risk children to identify and treat early, rather than late, signs of osteoporosis in those with limited potential for spontaneous recovery. In patients with extremely high risk of fractures (such as glucocorticoid [GC]-treated Duchenne muscular dystrophy [DMD]), the fracture rates are so high and the potential for spontaneous (medication-unassisted) recovery so limited that strategies to prevent first-ever fractures are currently under consideration.This chapter focuses on the evidence that shapes the current approach to diagnosis, monitoring, and treatment of osteoporosis in childhood, with emphasis on the key paediatric-specific biological principles that are pivotal to the overall approach, and on the main questions with which clinicians are faced during routine care. The scope of this chapter is to review the manifestations of and risk factors for primary and secondary osteoporosis in children, to discuss the definition of paediatric osteoporosis, and to provide specific recommendations for monitoring and prevention. As well, this chapter reviews when a child is a candidate for osteoporosis therapy, which agents and doses should be prescribed, the duration of therapy, how the response to therapy is evaluated, and the short- and long-term side effects of current treatments. With this information, the bone health clinician will be poised to diagnose osteoporosis in children, to identify when children need osteoporosis therapy and for how long, the safe administration of osteoporosis treatment, and the clinical outcomes that gauge treatment efficacy.