Vaginal Brenner tumor is extremely rare. Only five cases have been reported in the English literature to date. Here we report a vaginal Brenner tumor in a 76-year old postmenopausal woman, who presented with a 2.5cm-sized sessile vaginal polyp. Microscopically, it showed characteristic features of Brenner tumor consisting of three components; transitional islands, glands, and dense fibrous stroma. The epithelial tumor cells were positive for GATA-3, p63 and ER, but negative for PAX8. The origin of Brenner tumors in the vagina is unclear, but previous reports suggested of Müllerian origin. However, our case revealed that vaginal Walthard nests could be possible precursor lesions based on their immunohistochemical staining results.