Polycystic ovary syndrome is characterized by anovulation (amenorrhea, oligomenorrhea, irregular menstrual cycles) combined with symptoms of androgen excess (hirsutism, acne, alopecia). The clear definition and diagnosis in adolescents could be challenging considering that most of symptoms occur as part of the expected physiological hormonal imbalance of puberty. Therefore, different diagnostic criteria have been elaborated. Polycystic ovary syndrome could be associated to obesity, diabetes mellitus, and metabolic syndrome. In adolescents with polycystic ovary syndrome, adiposity is associated with higher androgen concentrations and greater menstrual irregularity. Polycystic ovary syndrome in youth is considered a risk factor for type 2 diabetes mellitus in adulthood. On the other hand, increased prevalence of polycystic ovary syndrome has been shown in type 1 diabetes mellitus. The treatment of polycystic ovary syndrome in adolescents is controversial considering that adequate trials are lacking. First-line treatment comprises lifestyle modification (preferably multicomponent including diet, exercise and behavioral strategies) that should be recommended overall in the patients with polycystic ovary syndrome and overweight, central obesity and insulin resistance. Beyond non-pharmacological therapy, pharmacological agents include combined hormonal contraceptives, metformin and anti-androgens, used separately or in combination. The aim of therapy is to bring back ovulation, to normalize menses, to reduce hirsutism and acne, to reduce weight. Other important goal is the treatment of hyperlipidemia and of hyperglycemia. This narrative review aimed to review the most pertinent literature about polycystic ovary syndrome in adolescents with obesity or diabetes. We overviewed the diagnostic criteria, the pathophysiology and the possible treatment approaches.