Granulosa cell tumors (GCT) of the ovary are prepubertal in 5% of the patients. In girls less than 20 years old, 80% of GCTs differ from those among adults. These juvenile granulosa cell tumors (JGCTs) are usually benign. GCTs belong to ovarian sex cord-stromal tumors, the more common ovarian tumors being epidermal and germinal. The etiology of GCT remains unknown. Most young children with GCT present with precorious pseudopuberty. Among adolescents GCT often causes menstrual irregularities, virilization, abdominal swelling, and pain. When JGCT is limited to the ovaries the outcome is excellent with only salpingo-oophorectomy. However, more widely spread tumors are difficult to treat and cause mortality. Cisplatin-containing chemotherapy can induce remissions in adult GCTs. Estrogens and peptide hormones, i.e., inhibin, are useful in the follow-up of the patients. The authors describe 3 children with GCT and review current data on this rare tumor from molecular biology to clinical aspects.