Introduction: Oral cancer also affects the oral epithelial tissue, known as the carcinoma of oral squamous cells. Moringa oleifera L leaves (MOL) is an alternative herbal medicine for use as an anticancer agent. The purpose of this study is to ascertain the function of Moringa oleifera L. Leaves extract to increase caspase 3 expressions in carsinoma of oral squamous cell. Methods: This study used 25 Rattus norvegicus that were randomly divided into five groups;K-(not given MOL extract and benzopyrene),K+(benzopyrene exposed and untreated), P1 (benzopyrene exposed and given MOL extract of 3,125%), P2(benzopyrene exposed and given MOL extract of 6,25%), P3 (benzopyrene exposed and given MOL extract of 9,375%). The caspase3 expression was obtained by immunohistochemistry techniques. The data were analyzed statistically with the One way Anova and Least Significance Difference(LSD) test. Results: One way anova test showed there was a significance difference of Caspase3 expression (p=0.000) between the groups. LSD test showed that P3 group has the most significant increased of caspase3 expressions. Conclusions: Moringa oleifera L.leaves extract with an optimum concentration of 9.375 percent could increase Caspase 3 expressions in oral squamous cell carcinoma.