Extraovarian sex cord–stromal tumor is an exceedingly uncommon entity that may cause a diagnostic dilemma clinically. We report a case of extraovarian fibroma with minor sex cord elements arising in the left broad ligament. The patient was a 66-year-old woman presenting with an intra-abdominal solid mass near the left ovary on magnetic resonance imaging. The tumor was located in the left broad ligament in contact with the left ovary and fallopian tube based on laparotomy findings. Histological examination revealed that the tumor was a fibroma that contained cell nests with aggregates resembling the Call-Exner bodies of granulosa cell tumors and irregularly shaped cell nests composed of undifferentiated sex cord–type cells. Cellular atypia or mitotic figures were not identified in any of the components. It was speculated that the possible site of origin of this tumor might be a supernumerary ovary in the broad ligament that was thought to be derived from embryonic remnants.