Background: Researchers are continuously working on formulating anticancer drugs of plant origin for treatment of oral cancer. Pumpkin seed oil is one of them. The use of nanoparticles as a drug delivery system has shown great success as it provides more selectivity and better drug efficiency. Aim: The following study was performed to determine whether the pumpkin seed oil (Cucurbita pepo L.) loaded Chitosan nanoparticle (NPSO_CH) has a cytotoxic and apoptotic effect on tongue squamous cell carcinoma cell line or not. Methodology: After obtaining the SCC-25 (tongue squamous carcinoma) cells, cell culture protocol was done according to standard procedures.  The cultures were treated with the serial concentrations of the Nano chitosan loaded pumpkin seed oil and Taxol drug, after that incubation is carried out for 48 h at 37ºC.  Chitosan/pumpkin seed oil nanoparticles were prepared using ionotropic gelation at room temperature. Caspase 9 enzyme essay was carried out using ROBONIK P2000 ELISA READER wl 450 nm. Results:  Results of  MTT cell cytotoxicity assay showed that there is an inverse relation between the serial NPSO_CH concentrations and Taxol drug on cell viability of tongue cancer cells (SCC-25). IC50 of NPSO_CH/SCC25 was 22.0±0.86 µg/ml while that of Taxol/SCC25 was 6.28±0.29 µg/ml. The caspase 9 enzyme assay revealed a significant increase of caspase 9 expression values after treatment of cancer cell lines SCC-25 with NPSO_CH and Taxol (18.63, 25.94 pg/ml) respectively, in comparison to the untreated control cancer cells line SCC-25(2.49 pg/ml) .