Background: Most of the conservative therapies used to treat lung cancer show serious side effects. In addition, the prevalence and death rates due to lung cancer have been increasing alarmingly across the globe. Eupatilin (EUP) is a naturally occurring flavone which is primarily the active ingredient of the traditional Chinese medicine Artemisia asiatica. Materials and Methods: In this study, we evaluated the antineoplastic effect of EUP against benzo(a)pyrene-induced lung cancer in Swiss albino mice. We analyzed the level of xenobiotics, liver dysfunction enzymes (LDEs), pro-inflammatory cytokines, and histology of the liver. Furthermore, we conducted in vitro experiments (A549 cells) to elucidate the amount of cell proliferation, apoptosis, and their markers (caspases 3 and 9). Results: The EUP (30 mg/kg bw) treatment of tumor-bearing mice with EUP revealed the normal levels of xenobiotic, LDEs, antioxidant enzymes, lipid peroxidation in the liver and further carcinoembryonic antigen, pro-inflammatory marker, and histology in lung tissues. EUP inhibited the proliferation of A549 cells and induced the formation of reactive oxygen species and apoptosis by upregulating the expression of caspases 3 and 9. Conclusion: Overall, these results substantiate the anti-neoplastic effects of EUP against carcinogen-induced lung cancer in in vitro and in vivo models.