Background: Globally, lung cancer is the second most cause of deaths, which accounts for approximately 29% of the cancer cases worldwide. d-Carvone is considered a vital constituent of many essential oils with immense pharmacological benefits. Objective: In this study, we examined the immunomodulatory effect of d-carvone in the Swiss albino mice model against benzo(a)pyrene (BaP)-induced lung carcinoma. Materials and Methods: BaP was orally administered to the mice (50 mg/kg body weight [bw] for 4 weeks [twice a week]). Post-BaP administration, d-carvone (20 mg/kg bw) was orally administered to the mice (20 mg/kg bw). We calculated the tumor incidence and performed the following measurements: lung and bw, hematological parameters, immune complexes (phagocytic and avidity indexes, nitroblue tetrazolium reduction, soluble immune complex levels, immunocompetent cells (leukocytes, lymphocytes, and neutrophils), immunoglobin (Ig) levels (IgG, IgA, and IgM), level of xenobiotics and enzymes that point toward hepatic dysfunction, carcinoembryonic antigen (CEA), and proinflammatory cytokines (PICs) in experimental and normal mice. The level of oxidative stress in the experimental animals was investigated. The lung tissues of investigational animals were examined for the histopathological changes. Results: According to the results, there was an increased level of lipid peroxidation and decreased level of antioxidant activity in the lung tumor samples. The counts of lymphocytes, polymorphonuclear cells, and macrophages were notably decreased and increased, respectively, by the d-carvone post-treatment. Moreover, BaP-induced inflammation that is indicated by the increased in the level of PICs and CEA proteins in lung samples. d-Carvone attenuated the levels of PICs and CEA. Conclusion: The results of this study reveal that d-carvone prevented the cells against BaP-induced inflammation in lung cancer without causing adverse effects.