Sclerosing stromal tumor (SST) is a rare sex cord stromal neoplasm of the ovary. Precocious puberty resulting from this tumor is extremely rare. We report a case of SST of the ovary in a 7-year-old Indian girl, who presented with the complaints of excessive development of breasts, early menarche, growth of pubic hairs, accelerated growth and abdominal distension. On clinical examination, a large rightsided abdomino-pelvic mass was palpable. Magnetic resonance imaging revealed a large, heterogeneous, solid and cystic tumor in the right adenexal region, suggestive of an ovarian neoplasm. Hormonal profile showed markedly elevated estradiol and low follicle stimulating hormone levels. Clinical diagnosis of precocious puberty with right-sided ovarian mass was thus concluded. Right-sided salpingo-oophorectomy was then performed. Histopathology showed features consistent with SST of the ovary. Postoperatively, signs and symptoms of precocity gradually regressed and her serum estradiol level came down to normal.