Extrauterine endometrial stromal sarcomas (ESSs) are quite rare tumors, and vagina is an unusual site for these tumors. This paper presents a very rare pathological entity of primary vaginal ESS. A 46-year-old woman with a complaint of postcoital vaginal bleeding, low abdominal pain, and constipation was admitted to the clinic. She had a mass of seven cm in size, located in the posterior fornix detected on physical examination. The preoperative biopsy showed ESS, surgical material, and evaluation of an endometrium confirmed the diagnosis of primary vaginal ESS. She underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, and partial vaginectomy. The diagnosis of ESS performed by pathologic and immunohistochemical evaluation was: caldesmon (-), actin (-), desmin (-). CD10 (+), ER (+), PR (+), and vimentin (+). There was no ESS lesion in the endometrium. The patient was free of tumor for 22 months after the surgery without any additional therapy. In this study, the authors report the sixth case of primary vaginal ESS in the literature and aim to discuss diagnostic criteria and management protocols in the light of the literature.