Virilizing adrenocortical carcinoma and Turner syndrome have opposite clinical manifestations in some aspects. Here, we report on the first case of virilizing adrenocortical carcinoma in a girl with Turner syndrome. A 2 10/12-year-old girl presented pubic hair of Tanner stage III with clitomegaly, deepening of her voice, and tall stature. No other morphologic anomaly was found. Biochemical assessment revealed normal electrolytes with pronounced elevation of adrenal androgens. She was found to have a large mass of the left adrenal gland on abdominal computed tomography scan. She underwent complete resection of the mass, and pathology was consistent with adrenocortical carcinoma. She was tested for TP53 gene mutation, and we found a de novo TP53 gene mutation (Val143Ala) as well as a 45,X karyotype.