Acute pelvic pain is one of the most common complaints of woman presenting in the emergency department. When gynecologic disorders are suspected, ultrasonography (US) is the modality of choice, enabling rapid diagnosis and decision making with regard to appropriate management. Frequent gynecologic etiologies include a large or enlarging simple ovarian cyst, hemorrhagic ovarian cyst or rupture of an ovarian cyst, acute pelvic inflammatory disease, and ovarian torsion. Endometriosis, uterine leiomyoma, and peritoneal inclusion cyst can also present as acute pelvic pain. Gynecologic disorders that cause acute pelvic pain frequently show characteristic ultrasonographic findings that enable specific diagnosis. In this review, the authors review ultrasonographic findings of gynecologic causes of acute pelvic pain.