Spindle cell carcinoma (SpCC), a variant of squamous cell carcinoma, is a biphasic malignant neoplasm that occurs mainly in the upper aerodigestive tract. It is uncommon in oral cavity, accounting for <1% of all tumors in oral cavity. Furthermore, it is uncommon for oral potentially malignant disorders such as leukoplakia to undergo transformation into SpCC. In this paper, we are reporting a case of SpCC of buccal mucosa in a 35-year-old female who was previously diagnosed with oral leukoplakia past 6 months.