Oral leukoplakia (OL) is the most common potentially malignant lesions of the oral cavity and Oral squamous cell carcinoma (OSCC) accounts more than 95% of all malignant neoplasms in the oral cavity. Therefore, the aim of this study to report the immunoexpression of metallothionein in dysplastic lesions to correlate with histological grade and OSCC. Samples of 5 normal oral mucosa, 15 dysplastic cases was graded as: mild dysplasia, moderate dysplasia and severe dysplasia and 15 cases of OSCC. Immunohistochemistry for the metallothionein was performed and the Pearson Chi-Square test was used in statistical analysis. The metallothionein stain in all cases exhibits a mosaic pattern and predominantly in cytoplasm and nucleus simultaneously. The total stain was significantly higher in OSCC when compared with normal and dysplastic lesions. Metallothionein expression may play an important role in the conversion of potentially malignant oral lesion to oral carcinoma since its earlier stages.