Herlyn-Werner-Wunderlich syndrome is a rare congenital anomaly of the Mullerian and Wolffian ductal system, manifesting as a triad of dipelphys uterus, obstructed hemivagina, and ipsilateral renal agenesis. Patients usually remain asymptomatic till menarche and experience progressive dysmenorrhea, suprapubic lump, and/or features of infection (pyometra, pelvic collection, etc.) afterward. We hereby present a case of a young lady with Herlyn-Werner-Wunderlich syndrome with a large endometriotic cyst, likely arising from the right hemiuterus. She presented with dysmenorrhea and progressive abdominal distention for seven years. She was treated by laparoscopic ovarian cyst excision and right hemihysterectomy that relieved her symptoms.