Smooth muscle neoplasms of the vulva are rare, and when localized in the Bartholin's gland, it can be mistaken as a benign lesion leading to a delay in diagnosis. We report a case of leiomyosarcoma of the Bartholin's gland in a 63-year-old postmenopausal woman, which clinically mimicked a chronic Bartholin's gland cyst. This case report emphasizes the importance of suspecting malignancy in any vulvar lesion in women of postmenopausal age, despite its location and asymptomatic appearance. A prompt, careful evaluation with adequate clinical judgment will help to manage such cases efficiently.