Anorexia nervosa (AN), a condition of malnutrition, has a multitude of effects, including low bone mineral density (BMD). Much has been discovered over the last couple of decades regarding the extent and pathophysiology of low BMD in AN, including the role of gonadal steroids, neuroendocrine hormones and appetite-regulating peptides. The effects of AN on bone are particularly concerning in adolescents, who are in the process of accruing peak bone mass, and decreased rates of bone-mass accrual in these critical years are predictive of poor bone health in later life. Although dual-energy x-ray absorptiometry continues to be the standard technique for monitoring BMD, newer techniques such as quantitative computed tomography and calcaneal ultrasound are being explored. Weight and menses recovery continue to be the most effective treatment for improving BMD in AN. Further research is needed to translate the pathophysiology being unraveled into clinical applications for improving BMD in AN.