Ovarian malignancies, although rare during adolescence, constitute the most common genital neoplasms in this age group. Germ cell tumors account for the majority of cases (61.5%), whereas 20% belong to the common epithelial group and 9.5% derive from sex cords and ovarian stroma. Dysgerminomas are the most frequent germ cell tumors. They are usually large and often secrete hormones and tumor markers that can be useful in monitoring the course of the disease. Diagnosis is often made in stage IA, and conservative surgery is the treatment of choice. In the epithelial neoplasm group, mucinous tumors are more common than usual (39.4% instead of 12%). The incidence of borderline tumors is also higher (30.3% versus 6-10%). Adnexectomy and, if needed, extirpation of peritoneal implants is considered adequate treatment. Sex cord-stromal tumors consist of epithelial (granulosa-Sertoli cells) and mesenchymal elements in a variety of combinations. Granulosa cell tumor is the most common subtype, presenting as the juvenile form in young females. It is of low malignant potential and is adequately treated with adnexectomy only.