Polycystic ovary syndrome (PCOS) is a relatively common disorder among adolescent women. The typical clinical features including menstrual irregularities and hirsutism are usually not apparent until middle to late adolescence. Yet studies suggest that PCOS may begin in early puberty. Young women with premature pubarche, a family history of PCOS, Caribbean Hispanic and African American ancestry, and/or obesity are more likely to develop PCOS. Adolescents with PCOS may have elevated total or free testosterone, androstenedione, and luteinizing hormone levels; insulin resistance; and hyperinsulinemia. The laboratory evaluation and management of the adolescent with suspected PCOS should be individualized on the basis of the clinical features and symptoms. The cornerstone of most treatment strategies includes either a combination oral contraceptive or progestin to decrease testosterone levels and regulate the menstrual cycle. Consideration of insulin-sensitizing agents, antiandrogens, topical treatments for acne and excess facial hair, and hair removal is dependent on the patient's symptoms and concerns. A healthy approach to eating, in some cases weight loss, and exercise is encouraged to reduce the risk of cardiovascular disease and type 2 diabetes mellitus. Management of the adolescent with PCOS is challenging and often requires a supportive, multidisciplinary team approach for optimal results.