BACKGROUND: Tongue cancer is one of the most common head and neck cancers in the world. Nowadays, natural compounds are important resources of many anti-cancer drugs. Venom from honey bees possesses potent anti-cancer activities. Cisplatin is a chemotherapeutic drug that has been used for decades to treat cancer cells. Recently, combination therapy has been a popular treatment choice for cancer patients. AIM: This study was conducted to evaluate the synergistic cytotoxic effect of honey bee venom (BV) and cisplatin on tongue squamous cell carcinoma 25 (SCC-25) cell lines. METHODS: The cytotoxic effect was determined using methyl thiazol tetrazolium assay, microscopic examination, real-time polymerase chain reaction (RT-PCR), and statistical analysis. RESULTS: The findings revealed that the cytotoxic potential of the tested drugs on SCC-25 cells was dose-dependent. Microscopic examination showed that BV and cisplatin alone and in combination mainly produced apoptotic cell death. Regarding RT-PCR results, P53 and caspase-3 expression levels were significantly increased in SCC-25-treated cells (p = 0.0001). CONCLUSION: The combined use of BV and cisplatin induced a marked synergistic cytotoxic effect on SCC-25 cell line.