Polycystic ovary syndrome (PCOS) can be identified in the adolescent years but is a process with genetic and epigenetic origins. Intrauterine growth retardation and premature adrenarche may precede the presentation of hyperandrogenism and oligo/anovulation. Other causes of hyperandrogenism and ovulatory dysfunction must be ruled out before PCOS is diagnosed. Obesity and insulin resistance often are associated features and greatly increase a girl's risk of developing metabolic syndrome and type 2 diabetes mellitus. Oral contraceptives, metformin, antiandrogens, and lifestyle modifications can have roles in alleviating the symptoms of PCOS and are reviewed in this article.