We present a case of ptosis secondary to metastatic lobular carcinoma of the breast which was initially diagnosed as involutional ptosis. A 67-year-old woman previously diagnosed with lobular carcinoma of the breast presented to our clinic with mild restriction of lateral gaze and persistent droopiness of her right eyelid (associated with decreased levator function) despite recent repair of a suspected involutional ptosis. Orbital magnetic resonance imaging revealed a mass in the right orbit which was biopsied and diagnosed as lobular carcinoma of the breast. Poor levator function is rarely present in involutional ptosis. Especially in conjunction with abnormal extraocular motility, other etiologies of acquired ptosis must be considered. This case highlights the importance of patient history and ocular examination in identifying the underlying etiology of ptosis. A review of the literature to evaluate the incidence of signs and symptoms associated with metastatic breast cancer to the orbit is included.