=Abstract Introduction: Sclerosing stromal tumor of the ovary is an extremely rare benign neoplasm that is mainly in the second and third decades of life. Most of cases, patients have pelvic pain or palpable abdominal mass. Hormonal effects include menstrual cycle disturbance or masculinizing are usually uncommon. Case: An 11-year old girl presented with deepening of voice. She showed clitoromeglay and male suprapubic hair pattern. Endocrine evaluation revealed elevated testosterone, androstenedione and dehydorepiandrosterone-sulfate. Pelvis MRI showed a 8.9x6.2x6.6 cm mass on the left ovary. Left oophrectomy was performed and microscopic examination confirmed sclerosing stromal tumor. Immunohistochemical studies showed a positive vimentin reaction and smooth muscle actin stains. Following surgery, the hormones level recovered to normal range. Conclusion: Herewith we present the case of sclerosing stromal tumor of ovary with virilization in a premenarchal girl.